Coming for USA and have a 4 hour layover in Guangzhou

I have a flight departing from USA and 4 hour layover in Guangzhou then taking a different airline to Kuala Lumpur do I need a visa? Also, after two weeks I will depart from Kuala Lumpur have another 4 hour layover in Guangzhou and then go back to USA. Because I'm coming two times in a short period of time will I need an entry permit?