United States companies all too often make the mistake of trying to protect their intellectual property from China by using a U.S. style non-disclosure agreement (NDA). These agreements do not work for China. Chinese companies know this and so they willingly sign them.
U.S. style NDAs focus on preventing disclosure of trade secrets to the public and they are written in English, subject to U.S. law, and exclusively enforceable in a U.S. city. These things all make complete sense if you are looking to stop an American company from revealing your trade secret, but this kind of NDA is of no value when dealing with your typical Chinese company based in China.
None.
First off, the fundamental issue when dealing with a Chinese company is not protecting your trade secret from being disclosed to the general public. The Chinese company that wants to steal your idea does not want to do so to reveal it to the general public; it steals your idea to use for its own benefit. This means your non disclosure contract with your Chinese counter-party must make clear that whether the information you provide is a trade secret or not, the Chinese company cannot use that information in competition with you.
Do not use a U.S. style non-disclosure agreement. Instead, use an NNN (non-disclosure, non-use, non-circumvention) agreement written to be enforceable in China. For all that entails, check out China NNN Agreements.