This project has evaluated several sand filters efficiency of Shuishang and Lantan drinking water treatment plant. The depth distribution of the medias, backwash efficiency and the property of medias were analyzed. The results of Shuishang drinking water treatment plant revealed that the first phase of filters has more medias depth shift different from the original design parameters compare to the second phase of filters. Both of the two phase filter have poor backwash efficiency. The effective diameter of the medias are smaller than the original design values. Besides, the uniformity coefficient of the anthracite could fit the regulations of lower than 1.7; while the coefficient of homogeneity of the sands couldn’t fit the regulations of lower than 1.5. The analysis results of sand filter in Lantan drinking water treatment plant also revealed poor backwash efficiency, and smaller medias effective diameter. The uniformity coefficient of the medias are similar to the results of Shuishang drinking water treatment plant. The most difference is the depth distribution doesn’t have significant shift comparing to the original design.