Hello, How to get a visa for internship in China for a period of less than 180 days.

Rody, if it is a paid internship, I’m afraid you need to apply for a work Z type for that.
You should first prepare those documents including your passport and copy of its data page, a completed application form, a recently-taken passport-style photo, alien employment permit and an invitation letter from a duly authorized unit (your employer will get the last two documents for you).