The invention discloses a roll groove design method for a seamless steel pipe stretch reducing machine set, which can reduce difficulty in optimal design and satisfy needs for product pipe profile and wall thickness control, and comprises the following steps: 1, collecting equipment parameters and variety specification ranges of a seamless steel pipe stretch reducing machine set; 2, selecting products of steel pipe representative specifications and determining the weighting coefficient of every specification; 3, setting a groove curve equation(Y=a0+a1*2+a2*4+,..., +an*2n) by using a0, a1, a2,..., and an as the groove curve parameters of the machine frames of the seamless steel pipe stretch reducing machine set; 4, setting a target function for optimizing groove curves, and determining the optimal values of the groove curve parameters by using an optimal design method; and 5, substituting the optimal values of the groove curve parameters into the groove curve function to obtain the required groove curves of every machine frame of the seamless steel pipe stretch reducing machine set. When the method of the invention is used, the optimization process of the groove design can be simplified, and the designed groove can meet the pipe profile requirements of products and has uniform wall thickness.