Abstract: Slow development of strength or super retarding may occur at top of cement slurry under large temperature difference during cementing of deep well, super-deep well, and long cementing intervals. To address these problems, an innovative heat-resistant retardant SCR180L was developed by using 2-Acrylamido-2-Methylpropane (AMPS), N-vinylpyrrolidone (NVP) and itaconic acid (IA) as raw materials. In addition, infrared spectrum was used to characterize structure of the co-polymer. Lab test showed that SCR180L can satisfy demands of cementing operations with circulation temperature of 70-180 ℃. Under 100 ℃ and 50 MPa, the thickening time of cement slurry with 0.9%-1.8% SCR180L is prolonged to 127-331 min. Under 150 ℃ and 70 MPa, the thickening time of cement slurry with 2.7%-3.6% SCR180L is further prolonged to 214-409 min. The more retardants added, the longer thickening time can be observed. Under temperature difference of 70 ℃, favorable growth of cement slurry strength is observed, with the cement strength at 24 h over 14 MPa. The retardant displayed high salinity resistance up to 18%. Field applications reveal that SCR180L has outstanding heat resistance and is applicable for a wide range of temperatures. With insignificant impacts on compression strength of the cement, the innovative retardant can satisfy demands for cementing operations in deep wells, super-deep wells, and long cementing intervals where large temperature difference may exist