Abstract: A novel two-step water-filling waveform design method based on Signal-to-Interference-plus-Noise Ratio (SINR) criterion is proposed to improve game performance of radar and jammer in this paper. There is a two-person zero-sum dynamic game between missile-borne radar and jammer in modern electronic warfare. Based on game theory, Stackelberg leadership models are established in clutter and noise. When radar is the game leader, the jammer uses water-filling method to minimize the output SINR. In order to reduce the impact of jamming, radar allocates signal power in frequency domain through two-step water-filling method. In the jammer-dominated game, radar makes use of max strategy to maximize SINR. The jammer improves jamming performance according to minmax strategy. Simulation results reveal that compared with min strategy, radar detection performance in maxmin strategy can be improved by 9.17%. In minmax strategy, target detection probability could decrease by up to 11.42% compared to max strategy. This demonstrates that two-step water-filling method provides a solution for waveform design in games.