A type of layered composite retarder, boric acid root intercalated hydrotalcite（Mg/Al-BA-LDH）was synthesized by ion exchange reaction between boric acid and magnesium aluminum lamellar dihydroxides（Mg/Al-CO3-LDH）which was prepared by coprecipitation method ,in order to well overcome the problems of abnormal cementing slurry and the strength of the cement paste developing slowly at the top of the long-sealing section cementing of the commonly used retarders.The structure was characterized by XRD、FTIR and SEM,results show that the prepared Mg/Al-BA-LDH has a good crystallite, and the interlayer spacing is 0.92nm at pH=4.5.At the same time,the comprehensive performance of the cement slurry system with Mg/Al-BA-LDH was evaluated.The experimental results show that the retarder can effectively adjust the thickening time of the cement slurry at 90 ℃~170℃,and the thickening curve is stable, indicating right-angle thickening.The compressive strength of cement stone containing Mg/Al-BA-LDH was greater than 14MPa at low temperature for 24h, and the strength can reach 33.97mpa after 7d when the content is 0.5%( Dosage is based on cement quality).After curing under different temperature difference conditions, the compressive strength of the top cement stone develops normally and meets the construction requirements, which could be applied to long sealing and large temperature range cementing operation. The filling of hydrotalcum material and the crystal effect played a leading role in the process of cement hydration, thus promoting cement hydration and effectively alleviating the slurry compressive strength decline caused by retarding effect.