Abstract: The horizontal wells with high pressure and low permeability need fracturing operation before being on production in West Sichuan, which puts forward higher requirements on the performance of cement slurry. The expansive agent, anti-channeling agent, stabilizer and plasticizer have been optimized and selected through indoor experiment, and a plastic expansion anti-channeling cement slurry system has been formed. The results of the laboratory show that the system has some features like API fluid loss less than 30mL, free liquid equal to 0mL, and SPN value less than 3. It has been successfully used in oil zone cementing on many horizontal wells such as XS21-3H, and satisfies the later staged fracturing production requirements.