The present disclosure provides a Complementary Metal Oxide Semiconductor (CMOS) video camera and method for filling light. The method includes: acquiring a frame interval and an exposure time of each line of pixels; determining a strobe period according to the acquired frame interval and exposure time of each line of pixels; and filling light for each frame of an image by using a light-filling lamp according to the determined strobe period and a predetermined duty cycle, wherein the predetermined duty cycle is larger than 0 and lower than 1. According to the present disclosure, the light-filling efficiency is improved, and the working life of the light-filling lamp is prolonged.