The concept of "legal requirement" can be pretty slippery here, and there are all sorts of possibilities for working around things...

The law generally states that a teacher must have a university degree of some kind. IMHO not necessarily a bad idea. However, in reality there are a lot of jobs that can be had without a degree.

The real rub comes down to getting you a work permit...the school must show the government some sort of qualification which could be construed as indicating that you might not be a complete idiot, and a uni degree is the usual solution to this. It's really not advisable to work here full-time without a residence permit, so it's an important consideration. Some places can use another shiny official-looking document- a TEFL certification, A Publishers' Clearing House Sweepstakes Finalist Notification, a Hallmark "World's Greatest Bowler" certificate, or something equally valuable- to get the job done. Some places have the local connections to just bull you through without any document at all....

Not having a degree won't necessarily prevent you from get a teaching job in China. It can, however, keep you out of many of the best jobs...especially if you also have no teaching experience. Government-connected jobs, such public schools and universities, often can't even consider you without a degree; nor will the more reputable private centers (if indeed there are any). It leaves you open mainly to the chain English mills, who will hire pretty much any Western mammal species with a pulse, and the more fly-by-night private schools...the places most likely to cause you problems once you're here.