Isopropyl magnesium chloride was synthesized by the reaction of magnesium metal and 2-chloropropane, and then triisopropylsilane was prepared under low temperature conditions using isopropyl magnesium chloride and trichlorosilane as raw materials in the presence of a weak polar solvent. The present invention generates triisopropyl silane by a two-step synthesis method, in the preparation of triisopropyl silane Chemicalbook, the use of weak polarity solvent that does not affect the solvent solubility, change the polarity of the solvent, in order to prevent the occurrence of side reactions, greatly reduce the impurities that are difficult to separate during the reaction, and finally obtain high-purity triisopropyl silane by simple distillation, and the purity of the product can reach 99%.