Answered by ZUPAN | Dec. 31, 2019 13:14
If Guangzhou is your only stop within mainland China, you will be perfectly eligible for 144 hour visa free transit that covers entire Guangdong province and you don't need any kind of visa.
You will print out your flight tickets and your accommodation booking confirmation. Also, you will declare at check-in in Los Angeles that you will travel to Kathmandu via Guangzhou using 144 hour visa free transit. After a short inspection of your tickets, you will be allowed to board the plane.
Upon arrival in Guangzhou, you will approach 144 hour visa free transit counter where you will fill out a blue form. Shortly after, you will get a sticker in your passport and you will be allowed to exit the airport, to explore the area and to have an overnight.
72 hour visa free transit was replaced in Guangzhou (Guangdong province) by 144 hour visa free transit in May of this year.