This study addresses challenges in noncooperative target laser methane telemetry, including complex noise, low signaltonoise ratio, and detection limit issues. We explore the application of wavelet denoising as a solution to these challenges. By analyzing actual measurement signals, we identify the coif5 waveletbased 7layer decomposition fixed soft threshold method as the optimal denoising approach. The performance parameters such as calibration, measurement error and detection limit of the telemetry system by wavelet denoising are studied. The results show that the measurement error range of the system after wavelet denoising is reduced from -2.89 %~7.20 % to -2.32 %~6.51 %, the detection limit was increased from 425.664 7×10-6 m（3σ） to 104.839 0×10-6 m（3σ）, and the detection limit was increased by 3 times. The selected wavelet denoising method significantly reduces complex noise in the noncooperative target laser methane telemetry system, potentially enhancing its detection performance.