According to China Eastern Airlines, for the flight courses between China and the United States, the passenger with economy class ticket is entitled to a baggage allowance for two pieces of baggage, each of which is less than 23KG. In addition, the total length of three sides of each baggage is less than 158CM. Besides, each adult passenger is allowed to take carry-on luggage less than 5 kg. If you get a through ticket, you luggage will be transferred automatically. Otherwise, you need to check it in Shanghai Airport again.