An accurate mathematical model for the precision retention of the five-axis machining center was put forward; on this basis, a spatial position precision retention model of the machining center based on rigid body dynamics was created to evaluate the machining center precision retention ability. The relationship between machining center precision and various errors was discussed. Taking a B-C five-axis machining center as the experimental object, the key precision indexes of the machining center were tracked for 743 days, the corresponding relationships between the precision indexes and the spatial coordinates of the machining center were found out, and the key error sources were identified; the law of the precision retention of the machining center changing with time was found out; the quantitative evaluation of precision retention of the machining center was completed, and the correctness of the proposed method and experimental model was verified. The results show that the position precision is the main factor affecting the precision retention of each axis; by using the proposed method, the key error traceability can be realized.