The sole data source of product is defined by 3D annotating technology, which contains all technical information of product and is a substitute for 2D drawing. Firstly, to solve the problems such as low efficiency and heavy workload of annotation inspection, the rationality of annotation is expounded and the common annotation issues are concluded. Secondly, after analyzing common annotation problems, an annotation element model (AEM) is proposed and the rules of annotation inspection are summarized, then establishing the datum and geometric element of AEM, whereas the annotations are checked term by term according to the criterions, and the reasonability of the relationships between the tolerance values on the same geometric element is measured consequently. Finally, based on CATIA system, automatic inspection function of geometric tolerance annotation is developed, which improves the annotation inspection efficiency.