The risk computation model and optimal strategy for radio frequency (RF) radiation on aircraft formation is investigated by analyzing the model of aircraft formation and the mechanism of electronic counter measures (ECM) between aircraft airborne radar and intercepting receiver. Regarding Schleher intercept factor as the risk index of ECM between aircraft and intercepting receiver, the factor is extended to the simple formation in the case of two aircraft, and the RF radiation risks of different formations are also compared. The computation model of Schleher intercept factor of RF radiation risk in the case of multiple aircrafts is presented by establishing the appropriate reference coordinate system. Regarding Schleher intercept factor of aircraft formation as the performance index, a stochastic optimal model is established for minimizing the RF radiation risk of aircraft formation. By analyzing the characters of performance index and using the basic inequality, the conclusion that the less the variance of the positions of aircraft formation in the flight airspace is, the less risk the RF will have can be obtained. Based on the conclusion, a simplified model of risk control of RF radiation in the case of multiple aircraft formation is established. Finally, the formation scheme of approximate optimization is proposed by the computer simulation in the case of 12- aircraft formation.