The invention provides a milling cutter service life control method. The method is characterized in that a milling cutter is used for surface milling of a gradient functional material, the sample of the gradient functional material is divided into a plurality of gradient regions, and an average milling cutter abrasion amount threshold value of each gradient region is obtained; and an optimal milling speed of each gradient region is calculated according to the average milling cutter abrasion amount threshold value, an actual abrasion amount of the milling cutter of each gradient region is obtained according to the optimal milling speed of each gradient region, and the service life of the milling cutter is controlled through the partition speed regulation. According to the milling cutter service life control method, on the premise that the cutting efficiency is not reduced, the cutter durability and the machined surface quality of large-plane milling machining of a dissimilar metal gradient functional material can be ensured; the service life of the milling cutter is controlled only by adjusting the milling speed, and the practicability is high; and the service life test duration ofthe milling cutter is generally not more than 5 hours, moreover, the test frequency is low, and the cost is low.