Aiming at the problems of noise and direct current (DC) drift in strain signal measurement, a suitable DC drift cancelation method is proposed based on studying the DC drift characteristics of strain signal. The signal is segmented according to local extremum points, and then polynomial fitting is performed on each segment. The onedimensional bilateral filtering is adopted to perform noise reduction processing for the drift cancelled signal, and the optimal parameter selection method of the bilateral filtering is proposed, and the denoising performance of the bilateral filtering is evaluated with signaltonoise ratio (SNR) as the index. The effectiveness of the proposed method was verified with experiment, in which the experiment data was the strain signal acquired from a force sensor in the minimally invasive surgery robot. Experiment results show that the improved piecewise polynomial fitting method effectively remove the DC drift of the strain signal, and the bilateral filtering method not only is suitable for the dynamic filtering of the signal, but also ensures excellent filtering effect. With the proposed strain signal processing method the resolution of the force sensor is better than 2 g.