Abstract: As domestic research of multi-beam echosounding detection is not mature, the reliability and accuracy of equipment quality and measurement data cannot be guaranteed. In view of this situation, this paper puts forward an uncertainty detection method of multi-beam echosounding based on an anechoic tank. The establishment of the detection software platform of sonar echosounding and the detection hardware platform of sonar echosounding based on the anechoic tank, eliminates or weakens the influence of the various errors and uncertainty factors caused by the experimental environment, thus greatly improving the accuracy and reliability of detection. Through detecting geometric index and precision evaluation analysis of the R2 Sonic2024 multi-beam echosounder the depth values of central beams are made to conform to normal distribution, the confidence interval is calculated, and the probability of falling into a confidence interval to eliminate discrepancy, to fit a confidence level of 95%, andcalculate the average of different values. The experimental results show that the uncertainty detection method of multi-beam echosounding is feasible; it can be used to objectively detect the uncertainty of multi-beam echosounder.