To investigate the jamming effect of high repetition rate lasers on pseudo random code laser semi active seekers,the required laser repetition rates and on target power densities for different jamming effects are calculatedbased on an analysisof the jamming mechanism of high repetition rate lasers.A tunable 1064 nm laser with a maximum repetition rate of 20 MHz is developed,and jamming experiments are conducted under various conditions.The results demonstrate that when the on target power density of jamming laser meets or exceeds the return signal of the target designator,jamming laser with a repetition rate above MHz range can achieve suppressive jamming on seekers,causing the seekers’ information processing units to fail.The research can provide engineering application references for high repetition rate laser jamming against pseudo random code laser guided weapons.