The light absorption characteristics of the bacteriorhodopsin(BR) have been studied as function of relationship between absorbance and mass concentration of BR suspension, pH and temperature of BR suspension. It was found that the absorbance is linearly related to the mass concentration of BR suspension. When pH increased from 5 to 8, BR was stable; when pH was greater than 8 or lower than 5, the following functional relation between pH and absorbance can be obtained, respectively : (33 19-86 21 A ) 0.5 =pH-7 80, (57 33-133 3 A ) 0.5 =7 09-pH. No obvious variation of absorbance of BR suspension was observed at temperature from 0 to 30 ℃, but absorbance was found to be decreased markedly at temperature higher than 30 ℃. The pH of BR suspension increased with the temperature.
