In order to improve the adaptability of laser fuse in smoky environment, the echoing characteristics of linear frequency modulated (LFM) pulse laser fuse is studied. The laser scattering model in smoke is established by optimizing the calculation speed of Monte Carlo algorithm. The results show that the echoing signal of LFM pulse in smoke is composed of three types. They are low frequency (LF), high frequency (HF) and target signal. When the smoke concentration is 1.4 mg/m³, the target signal is completely attenuated. Although the LF of smoke has little effect on target signal detection, when the smoke concentration is greater than 1.2 mg/m³, the aliasing of smoke HF and target signal spectrum causes the laser fuse to generate false alarm signals. Compared with traditional pulse lasers, LFM pulse lasers can adapt to higher concentrations smoke. The wider the bandwidth, the stronger the ability to resist smoke interference. The research results provide important support for the design and signal processing of LFM pulse laser fuses.