The invention discloses a preparation method of a catalyst used for hydroformylation of olefins and relates to the technical field of catalysts. The preparation method comprises the following steps: Step 1, adding methyltrichlorosilane, acetone and RhCl3.3H2O into a constant temperature magnetic stirring water-bath having a reflux unit container; heating for two times (heating temperature for thefirst time is 30 DEG C and the heating temperature for the second time is 60 DEG C), stirring to obtain a uniform mixed solution; Step 2, adding a catalyst into the mixed solution obtained in the Step1, introducing into a porous material, and polymerizing until a solid product is obtained; and Step 3, carrying out coordination between the solid product and metal salt to obtain a solid catalyst, namely the polymer composite catalyst. The stability of the catalyst is improved, and time is saved. The method is convenient to use and simple to operate. Meanwhile, the catalyst has high catalytic effect, efficiency can be raised, and raw materials can be saved.