The photovoltaic effects of chlorophyll-a(chla) and the effects of stearic acid, egg phosphatide and cholesterol on those were investigated by means of measuring the photoinduced potentials of SnO2/chla electrodes. Because of the formation of liquid crystal states, appropriate concentrations of stearic acid and egg phosphatide added in a certain system could increase the photovoltaic effects of chla. Cholesterol always decreased the photovoltaic effects of chla because there was no liquid crystal state formed with it. The photovoltaic effects of chlorophyll-a (chla) and the effects of stearic acid, egg phosphatide and cholesterol on those were investigated by means of measuring the photoinduced potentials of SnO2 / chla electrodes. Because of the formation of liquid crystal states, appropriate concentrations of stearic acid and egg phosphatide added in a certain system could increase the photovoltaic effects of chla. Cholesterol always decreased the photovoltaic effects of chla because there was no liquid crystal state formed with it.