The invention provides a motor for an electric tool with an adjustable inner diameter of a stator. The motor includes a stator assembly and a rotor assembly arranged in the stator assembly, wherein the stator assembly includes a stator yoke and multiple stator teeth, an inner side of the stator yoke is uniformly equipped with multiple grooves, at least one side wall of each of the grooves is equipped with a first tooth portion, the stator teeth respectively include base portions and integrated shoulder portions, one side surface of each of the base portions is equipped with a second tooth portion, one side of each of the base portions is embedded in the groove, and the second tooth portion arranged at one side surface of each of the base portions is at least partially engaged with the first tooth portion. The motor is advantaged in that during large-scale motor production, for the same size of the stator assemblies, only stator yokes and stator teeth need to be mass-produced, assembling can be performed only according to the calculated yoke gaps during assembling, so production design efficiency is improved, economic performance of motor production is improved, the power density ofthe shaped motor can be further improved by fine tuning of the gaps of the yoke, and performance of the motor is maximized.