The invention provides a machine tool main-shaft bearing heat production calculation method based on a dynamical model. The machine tool main-shaft bearing heat production calculation method comprises the steps of 1) simplifying a machine tool main-shaft structure into a bearing-rotor system; 2) establishing a dynamical model of the machine tool main shaft; 3) calculating relative friction force and relative speed between a bearing ball and inner and outer rings according to the dynamical model of the machine tool main shaft, and further obtaining the bearing heat production conditions under the effect of each ball; and 4) enabling the heat production amount of each ball in the bearing to be overlaid to obtain the heat production condition of each part of the overall bearing, namely, the heat production conditions of the bearing inner ring, outer ring and the ball. By adoption of the machine tool main-shaft bearing heat production calculation method, the heat production condition in the bearing under the stable operating state of the main shaft system can be accurately worked out through the way of the dynamical model; meanwhile, through the characteristics of the dynamical model, the heat production conditions of the bearing under different working conditions, such as different rotary speeds, loads and pre-tightening force can be analyzed, so that a good analysis foundation is provided for the heat analysis of the main shaft structure; and meanwhile, evidence is provided for accurate heat error prediction, so that the machining precision of the machine tool is further ensured.