Abstract: Suppose that the difference between the practical technical parameter and the designed standard is normally distributed with zero valued positional parameter,a multiple Bayesian testing rule on the ratio of error standard deviation in accordance with two lots of error sample is presented.The joint prior distribution of two standard deviation parameters is due to Jeffreys',and the theoretical foundation of deduction is the maximum posterior probability rule.Finally,a practical example is given to illustrate how to use this testing rule.