Fluid loss additives can control fluid loss to the layer, prevent Mud density from increasing caused by over dehydration which will lead to pumping problem and cementing accidents in case of cementation. AMPS polymer fluid loss additives have following advantages: wide applicable temperature, salt-tolerance, stability and suitable for all API classes of cement and no water quality required. AMPS polymer fluid loss additives can be used in general system（≤150℃）and high temperature system (≤180℃). AMPS polymer fluid loss additives have dry-mixed type, water-mixed type and dry＆water mixed dual purpose type according to the method of use. There are also high purity type fluid loss additives with the advantages of high purity and small dosage that can be used to make other products.