The light current of biochemical sensors based on the light addressabl e potentiometric sensor (LAPS) technology is a kind of weak non-stationary signal with low signal-to-noise ratio (SNR).Hence,in o rder to extract clear photocurrent signal,this article adopts the method of wavelet transform for denoising processing.The LAPS signal is decomposed into t hree layers by wavelet transform with the wavelet coefficients and threshold of each layer.The new wavelet coefficients are obtained after processing the original ones according to the threshold and the characteristics of each layer.Finally,the signal is reconstructed according to the new coefficients.We f ind that the new LAPS signal spectrum is valid.The SNR a nd smoo thness of the LAPS signal obtained from wavelet denoising are higher than those from the Fourier denoising,which indicates that the wavelet transform is an ef fective method for LAPS signal denoising.