The environment-friendly starch fluid loss additive is a kind of fluid lossadditive product synthesized with starch as the main raw material. lt ismainly used for the control of filtration loss of water-based mud. This product can be used not only in fresh water drilling fluid, but also in seawater and saturated salt water drilling fluid, with good salt resistance.Compared with common starch filtration reducer, this product can effectively solve the problems of product failure and mud performance deterioration caused by fermentation and odor during use.