I,m traveling from Guangzhou to Hong Kong. How pieces of luggage, size and weight?

If you choose to go to HK by airplane, for economy class passengers, you may take one item of hand baggage which should be less than 20×40×55 centimeters (8×16×22 inches). The total weight should be no more than 5 kg (11 pounds). The first class and the business class passengers may have two items of hand baggage and total weight should be limited in 8 kg (17.6 pounds).
As for the free checked luggage, first class passengers can take a bag no more than 40 kilograms and the business class as well as economy passengers are 30 and 20 kilograms.
If you want to go to HK from Luohu, there is no such limitation.