The invention discloses an optimization method of pipeline surveying and mapping internal inspection IMU data preprocessing. The method comprises the following steps: firstly, determining an estimatedvalue of an initial attitude angle of an IMU by measuring a physical dimension of a ball serving barrel; then performing initial alignment of a static base by using two iterative filtering data to becompared to respectively obtain a course angle and an elevation angle, and calculating alignment errors of the course angle and the elevation angle; and then using a difference value of absolute values of the alignment errors as a criterion to evaluate the effect of the twice iterative filtering. By adoption of the method, the filtering effects of different iterations can be compared to a certainextent to prompt the over-filtering situation and to optimize the preprocessing algorithm. Compared with the manner of directly comparing the matching degree of a solution trajectory and a checkpoint, the method is more efficient, the most of confounding factors are removed from the iteration for terminating the iteration, the method is more convincing, the over-filtering situation is basically avoided, and the optimization of the data preprocessing algorithm is achieved.