In a landing system, each airplane's asking signal contributes to the interference seen by the other airplanes when it is ranging through asking-replying. In a given condition of limited available power, a reliable and effective power control strategy is needed. According to whether the ground station transmits instructions of power control, this research is made up of two parts. With no communication power control method, the equation of transmitting power is deduced and the shortage of the method is analyzed. The research places emphasis on the analysis of power control of fixed step and based on Nash game in the situation that the ground station needs to transmit instructions. Every method above has been simulated and the advantages and disadvantages are expatiated respectively through comparison. The method based on Nash game has a faster constringency and transmitting power stays at a lower level than fixed step, which means that the use of the method based on Nash game reduces the transmitting power and saves energy. So the method can meet the demands of high dynamic body like airplane. This scheme may provide a reference for the choice of power control strategy.