Abstract: One-dimensional linear accumulation method is used in the conventional tolerance analysis for the pressure water reactor driveline, which is too conservative. Limit calculation cannot be used in the conventional analysis method, and there is no guanrantee for 100% confidence level of tolerance design. To solve this problem, a 3-dimensional (3D) dynamic tolerance analysis method for the driveline is proposed. The dynamic change of the drive rod from vertical state to oblique state is analyzed. The first contact point and the second contact point are used as the double reference to restrain the offset direction and range of drive rod and its passage. 3D dynamic tolerance analysis method improves the accuracy of the analysis and reduces the conservativeness of the calculation. The validity of this method is verified by the control rod drive line cold test on the  modular samll reactor (ACP100).