Geometric tolerances refer to macro-scale errors in the shape and relative positions of geometric features on a product. These parameters critically influence assembly performance, functional characteristics, and other aspects. Coordinate Measuring Machines (CMM) are commonly used for geometric tolerance inspection. However, current CMM measurement point planning primarily relies on empirical methods, which compromises both the efficiency and reliability of product acceptance. By analyzing the sources of CMM measurement uncertainty, this study establishes a calculation method for point uncertainty. A Monte Carlo simulation-based model is developed to simulate measurement uncertainty, revealing the relationship between the number of measurement points, point uncertainty, and the resulting measurement uncertainty. Furthermore, a measurement point planning model is proposed to determine the minimum number of measurement points required for geometric tolerances under specified conditions. Experimental results demonstrate that the proposed method ensures measurement uncertainties remain below maximum allowable thresholds. Compared to the standard HB 20478–2018, the measurement point layouts planned by this method are more rational and effective.