join with wife in china, which kind of visa do I need?

If you want to do business visa in China, you need to apply for a business visa. FYI: https://www.travelchinaguide.com/embassy/visa/business.htm
If you want to work in China, you need to apply for a work visa. FYI: https://www.travelchinaguide.com/embassy/visa/work.htm
In you case, you can also apply for a family visit visa to stay with your wife iin China for a relatively long time. But this kind of visa doesn't allow you to work in China. If you still want to apply for this kind of visa, you can first apply for a tourist visa to enter China and then change it to a family visit visa upon arrival. FYI: https://www.travelchinaguide.com/embassy/visa/family-visit-permit.htm