The diameter of ball-little-spindle and diameter high-accuracy batch measurement are difficult problem in the work. To this urgent problem, the author of this article has designed the comparative measurement device of a kind of tangent organization type, not only a better one solving the measurement problem in batches, but also the precision is high. This article has introduced the composition structure and operation principle of this set of devices especially and analysed its characteristic and advantage. At last, the measurement uncertainty has been provided.