What's the name of the staff in charge of airport customs clearance?

It's not as simple as you think. The so-called customs clearance refers to a situation that occurs in international passenger and cargo transportation. Customs clearance must go through inspection and quarantine, border inspection and customs clearance. Anyone who fails to enter the country will be stopped. The one you are talking about is called border inspection. Abroad, it is called immigration bureau, and internationally, it is called immigration bureau. You can check it online. There are civil servants directly under the Ministry of Public Security and the Armed Police in China to do this work.