What would happen if the us trade with china ended?

What would happen if the us trade with china ended?
It would depend on the nature of the ending.

If trade between the US and China ended abruptly, there would be a backlash period until each nation's economy could recover. Such a large percentage of each nation's trade is with each other that the effect would be widespread and devastating for both countries. It would result in economic problems felt by most of the world (to one extent or another). In the US, local goods would become prohibitively expensive, and the economy would struggle. In China, local goods would become virtually worthless, and their economy would struggle also. As with any situation, eventually an equilibrium would be found. The question is how much damage would be caused in the interim period.