The adjacent channel interference of VHF communications has always been a difficult issue in the field of air traffic control. As an ATC equipment support department, it is necessary to find effective measures to suppress adjacent channel interference. Through the problems in the apron tower of the Chongqing airport, the definition of adjacent channel interference of VHF communications is introduced, and the mechanism of adjacent channel interference is analyzed. The measures to suppress the adjacent channel interference has been proposed, and the practice shows that these methods are effective. Increasing the system isolation between transmitter and receiver can effectively solve the problem of adjacent channel transmitter and receiver in VHF communication.