The PCT is a relevant patent the international treaty of the application.According to the PCT provision, the patent applicant can deliver to through a PCT path international application, appointed to world almost all nation(include Europe) application patent, can the priority term is from 12 months extension to 30 months to its member country application nation patent.

The PCT international application include two stage:International stage and nation stage.
(1)In China hand over the PCT international application(namely international stage) to mostly is divided into the following step:
1. Put forward an application.Applicant can at China previously application of application day(priority day) since in 12 months with Chinese to China nation the intelligent property right bureau put forward PCT international application, and request China of priority, have never need to hand over a priority certificate.
2. China nation intelligent property right bureau conduct and actions accept a bureau to accept patent application, and Be international index unit according to international index report.Applicant can according to above of index report, as to it's patent application the document carry on modification.
3. The nations announce patent an application.International bureau will in from priority day since full 18 months namely the line announce.
4. Put forward international first step a reviewing claim.Applicant should in the application in the meantime or at from priority day since put forward international first trial claim in 19 months, and pay reviewing fee.
5. International first trial unit according to international first trial report, applicant can according to should report as to it's patent application the document carry on modification.
(2) Nation stage:
Applicant can at from priority day since expire for 30 months before the choice PCT member's country, and to should country patent bureau application it nation patent, namely:Turn into the nation stage of that country.
The PCT is international application into nation stage, must application document translation is application country of authorities language, it main procedure with at domestic application patent homology, then include:The application get into, announce, substantial reviewing, authorization etc. procedure.For practical new, majority the nation need not substantial reviewing then authorization;Some nation doesn't have the practical new patent, such as:The United States, Canada, England etc., at these nation can application invention patent.
Although nation the expenses of the stage with alone at each nation application nation the expenses of the patent about, its advantage is can the priority term is from 12 months extension to 30 months to its member country application nation patent(some nation or the region can postpone to 31 months), make the applicant have more time to decision get into which nation application homology topic of patent, and according to index report and first trial report modification patent application document, with satisfy invention creation of novel, create sex and patent.
Completion get into a dissimilarity nation of nation stage of work after, the applicant then own a dissimilarity nation of patent, they are mutually independence, each demand pay the fee in year.
According to patent method in China Article 20 of request, any China unit or personal outwardly country application patent of, all demand entrust a nation appointed of have already concerned foreign affairs agency qualifications of the patent agency carry out,Applicant general need 2~3 months in advance assurance get into which nation of nation stage, and entrust to concern foreign affairs an agency start translation and document preparation work.At sign with my company to concern foreign affairs patent to act for contract and the expenses pay contract engagement after, can immediately get into application procedure.

*All member national capital of PCT treaty obey the PCT treaty chapter 2 in relevant international first step reviewing of provision.
1 according to treaty 64(5) put forward declare.
2 according to treaty 64(2)(a)(ii) put forward declare.
3 the part and region included an overseas.
4 rightnesses are in Europe of Kingdom mainland, the lotus belong to Anne ground row Si islands with Lu Ba Dao3 valid.
5 extensions arrive a person an island.(the some places translate Manx)
6 according to treaty 64(3)(a) with 64(4)( a) put forward declare.
7 extension go to all from the United States negative have an international responsibility of district.