Objective To measure arm's tremor of patients with neurological disease quantitatively. Methods Film images of light points which are irradiated to the center of cross, then the images are digitalized by computer. The maximum distance of light points departing the center of cross MR?the average distance of light points departing the center of cross AR and the total length of the track of light points TL are calculated. Results MR?AR?TL of patients with neurological disease are significantly different from those of normal people(P<0.05).Conclusion MR ?AR?TL can be referred as quantitative indexes of arm's tremor of patients with neurological disease.