Effective attenuation coefficients and diffuse reflectance spectra of acupuncture point and non-acupuncture point were measured in vivo before and after the brachial artery was constricted with a sphygmomanometer. Experimental results showed that the effective attenuation coefficient of acupuncture point was smaller than that of non-acupuncture point. When the brachial artery was constricted, the effective attenuation coefficients of acupuncture point and non-acupuncture point increased. Furthermore, the increasing amplitude of effective attenuation coefficient of acupuncture point was smaller than that of the non-acupuncture point. Diffuse reflectance of acupuncture point was lower than that of non-acupuncture point within the wavelength range of 470 to 600 nm. Both the diffuse reflectance of acupuncture point and nonacupuncture point decreased after the brachial artery was constricted. These experimental results indicated that the optical characteristics of acupuncture point tissues were correlated with the physiologic changes. Therefore, these optical characteristics of acupuncture points would be helpful to study the mechanism of acupuncture meridian.