Abstract: Considering the characteristics of fine pitch gears and limitations of traditional gear single-flank rolling tester (GSRT),a new tester for fine-pitch gears has been developed based on a novel method of GSRT with two driving motors.The key techniques,such as mounting and positioning of micro fine-pitch gear,measurement of micro angle displacement and so on,were researched.The tester,with vertical configuration,mainly consists of base,precision spindle,micro angle displacement measurement unit and control unit.As a new approach for the inspection of fine-pitch gears,the tester can inspect the transmission errors for fine-pitch gears.