Hi, Do I need to book with the same airlines for two of my connecting flights? for 24h transfer.

No, you do not. It is allowed to travel on two separate tickets and to fly on two unrelated airlines.

You should print out your flight tickets and your hotel booking confirmation if your transit is during the night and have those printouts with you, at hand. Upon landing in China, you will immediately approach transit counter where you will apply for a temporary entry permit by presenting those printouts. This application is for free. When your permit is granted, you will cross the immigration, collect your baggage and proceed with your plans for your onward flight out of China.

You have to be aware that your total transit time in China cannot exceed 24 hours.