The measuring method and data processing of tooth surface deviation based on gear measurement is presented and investigated. On the basis of the mathematic model of tooth surface generating

the coordinate value and normal direction cosine of measured points

at the tooth surface

and the three-dimension map of tooth surface is partitioned and produced

are calculated. After the measuring experiments in JD45 have been done

the real normal direction deviation of tooth surface is obtained by means of the curved surface match principle and the related theory of errors compensation. The results of the measuring comparison show a good agreement. The programme gives support for close-loop technique of manufacture.