Micro gears are applied in an increasing quantity in many applications. Therefore, precise measurements are of growing importance to ensure their quality. This paper studies the electronic generative and automatic indexing measurement system in a micro gear (with a module less than 0.2mm) measuring instrument, and develops a loop proportioned driving approach and a stage-error compensation technique. The approach and the technique have been successfully applied in the micro gear measuring instrument developed by the authors. The experiment shows that the application of the approach and the technique greatly reduces the cost of measuring instrument, with simple control and reliable operation.