Abstract: Hybrid LFM-frequency encoding low probability of interception (LPI) waveform combines the techniques of LFM and FSK, which can obtain a large time-bandwith product, thus enhancing the capability of LPI. However, hybrid LFM/FSK LPI signal suffers from high range sidelobes, resulting in the decrease of radar detectability. To this end, this paper deals with the problem of sidelobe suppression. Specifically, the specific sidelobe suppression filter selected from its library which is designed off-line, instead of matched filter or correlation, is exploited on the echo signal. This operation can accomplish the compression pulse while achieving low sidelobes, and its engineering implementation is simple. Simulation results illustrate the effectiveness of the devised filter, showing its ability to obtain lower sidelobes in comparison with the traditional process.