I want to marry a lady here on a visa from china. If I marry her can she stay with me here and get a green card to work in the usa. Is it leagle to get married now while she is her and does she need to applie to get a imagration green card

No matter what, you will need to apply for a visa. However, since she is already here, do so from here. If she goes back to China, prior to receiving a resident visa, it will take years to go through the red tape.

Best thing you can do is get a qualified attorney to advise you further. It will cost, but is well worth it.

I can tell you from experience that you should try to keep her here in the USA. My sister and now brother in law went through this. It took years. Also, when he came over on a visitors visa, customs found (illegally) a letter to my sister, discussing the wedding. Well, my brother in law was denied entry and put right back on a plane, only days before their wedding date. Proceed with caution, but make sure you follow the rules.

Good luck and congratulations.