Abstract: After light and dark adaptation,the retina of the Macrobrachium rosenber was respective incubated in high calcium solution,physiological solution and low calcium solution.Soluble Gq α was extracted from the retina of the Macrobrachium rosenber with protein extract and was electophoresised by SDS-PAGE.The percent of the soluble Gq α was analyzed by Tanon GIS gel image disposal system.After the incubation in three solutions,the soluble Gq α in 42 kDa was all extracted from photoreceptor cell.The percent of the soluble Gq α in photoreceptor cell in high calcium solution,physiological solution and low calcium solution was 3.13%,3.09% and 3.03% respectively on light adaptation and was 3.17%,3.06% and 3.01% respectively on dark adaptation.In physiological solution and low calcium solution,the percent of the protein on light adaptation was higher than that on dark adaptation,but in low calcium solution,the percent of the protein on light and dark adaptation was no significantly different;in high calcium solution,the percent of the protein on dark adaptation was higher than that on light adaptation.This was probably relevant to feedback regulation.