The pulse wave signal collected by optical capacitance product method is easy to be interfered and the baseline drift noise occurs. An improved variational mode decomposition (VMD) algorithm is proposed to eliminate baseline drift noise. Firstly, the PPG signal is resolved into multi-modal components by means of variational mode decomposition, and the residual items of empirical mode decomposition (EMD) are eliminated. Finally, all modes are reconstructed. The experimental results show that the signal with drift effectivity could be reduced by the algorithm. Compared with the EMD algorithm, the noise of signal reduce ratio and mean square error of the improved VMD algorithm are 0. 26 and 1. 73, which can improve the quality of signals effectively.