Abstract: This study was conducted to compare the effect of monochromatic light on expression of c-Fos in the SGC of optic tectum and SCN in broilers. Forty onedayold male AA (Arbor Acres) broilers were respectively reared under four light treatments, white (400-760 nm), red (660 nm), green (560 nm), blue (480 nm) by using LED (light-emitting diodes) as light sources until the 14th day.Light intensity was 15 lx. Light exposure was scheduled for 20 hours of light and 4 hours of darkness during the entire experiment. The results showed: in the SCN, c-Fos expression of BL group were significantly lower by 29.76%， 17.88% and 22.23% than that of WL, RL and GL groups respectively (P<0.05), no significant difference were found among WL, RL and GL groups (P>0.05). Similarly, c-Fos expression of BL group were significantly lower by 17.78%， 21.75% and 23.63%than that of WL, RL and GL groups, respectively (P<0.05), no significant difference were also found among WL, RL and GL groups in the SGC of optic tectum (P>0.05). These results suggested that blue light suppress c-Fos expression of neuron in the SCN and SGC of optic tectum compare to red and green light to some extent.