The silver colloids were prepared by ultraviolet photochemical method. It was found that the position of the absorption maximum of the silver colloids gradually blue shift with the concentration of the silver nitrate increasing and then the position of the absorption maximum of the silver colloids gradually red shift with the concentration of the silver nitrate increasing. Also, it was found the position of the silver colloids absorption maximum does not change, but the value of absorption maximum increases with the concentration of trisodium citrate. The TEM image of the silver colloids shows that the scale of the silver particle change from 5 nm to 20 nm.