The invention discloses a method and device for measuring, predicting and optimizing milling tool marks on the top surface of an engine cylinder block. The method comprises the steps that preprocessing of cylinder block top surface point cloud data obtained through high-definition measurement is conducted, abnormal outliers are removed, filtering of the point cloud data is conducted, the tool mark features in a high-pass signal are extracted, and a three-dimensional evaluation index of the tool marks is defined; according to the milling machining characteristics of the top face of the engine cylinder block, influences caused by spindle inclination, tool abrasion and tool jumping are comprehensively considered, and physical modeling is conducted on the tool mark forming process; and the milling surface quality is predicated according to a tool mark physical model, a three-dimensional evaluation index numerical value of the tool marks generated under a specific process parameter condition is calculated, a process parameter multi-target optimization model is established on the basis, and an optimization model is solved to obtain an optimal process parameter scheme suitable for milling the top surface of the engine cylinder block. According to the method, milling surface tool mark feature indexes are defined and accurately predicted, so that the milling process parameters of the top surface of the engine cylinder block are effectively optimized, and the milling quality of the top surface of the engine cylinder block is improved.