You can't have EI and return to China (Unless you are in maternity/parental leave). There is heavy fine if you are found in frault. My suggestion is do it legally, otherwise you might bring yourself more trouble than you would thought.
If you are out of the country for less than 3 weeks, you can claim that you are back to China to look for jobs. Then your EI will still be payed. But you have to get permission first.
Some material on job fairs (that you plan to attend) or interview notice in China will help.