The current aircraft ground air conditioning environment is complicated.There are few efficient methods targeting the online traffic detection problem.This paper proposed an online flow detection method of noncontact ultrasonic gas flowmeter DSP and FPGA processing system based on DSP chip of T1 company, which is responsible for controlling the flow in the process of detection and processing of ultrasonic signal the selected FPGA chip. Altera group is responsible for the completion of the ultrasonic transducer excitation and receiving signal high frequency sampling design of aircraft ground air traffic monitoring system.The feasibility and adaptability of the method wasproved by tests.