Abstract: In response to the current situation that radar echo loss is unclear caused by blanking, the loss probabilities of the radar echoes caused by the blanking were studied, and the impact of the blanking on signal-to-noise ratio in detecting was evaluated. The influence of the blanking on the radar echo waveforms was investigated. The response, namely the output of the matched filter to the residual after the echo being erased by the blanking gate, was derived. Based on the technology of radar detecting, the moment of detecting the target and the change of detection voltage of the radar with the blanking gate were studied, and the equivalent loss probabilities of the echo were defined. The varying rule of the residual echo being analyzed, the expressions were derived for the average loss probabilities and the loss probabilities of the periodic echoes both caused by the periodic blanking gates. Also, the expression was obtained for the average loss probabilities of the echoes caused by blanking gates with time-varying duty cycles. The verification was implemented by a simulation. Each loss probability of the echoes was compared with a combination of the calculation results and numerical simulation. The maximum absolute deviation between the two was about 1.21%, which could be ignored. Finally, by theoretical calculations and simulation verification, the matched filter output of residual linear frequency modulation echoes was analyzed, and the influence of blanking on the pulse accumulation for coherent radar was investigated. The mathematical models for the loss probabilities and the average loss probabilities of the echoes are obtained as well as the decrease degree of signal-to-noise ratio in detecting caused by blanking. The research has achieved a quantitative evaluation of the impact of the blanking on the loss of the echo, which provides support for accurately analyzing the detection performance of the radar with the blanking and making decisions on the use of blanking measures.