The invention discloses an improved SMSP interference method for a linear frequency modulation radar, which belongs to the field of radar electronic confrontation. The method provided by the invention comprises the steps that a jammer receives a radar signal, and converts the signal into an intermediate frequency signal through the down frequency conversion of a mixer; the converted radar intermediate frequency signal is sent into an A/D converter through a low-pass filter, and is sampled through a high speed clock; radar pulse signals are grouped, copied and spliced into a complete radar pulse string, and the new complete radar pulse string is modulated; the modulated pulse undergoes D/A conversion, and then is sent into the low-pass filter; and a pulse jamming signal after low-pass filtering is up-frequency-converted through the mixer to the center carrier frequency of the radar and is emitted. According to the invention, a sub-pulse string cycle forwarding working mode is used; a sub-pulse string signal and the radar signal contain the same frequency modulation slope, and match the matched filter of the radar signal; and a false target can be generated on the radar receiving end for cheating.