The works is relied on the mass prestressed sewage tank, the tendon loss of prestress is calculated. Value of equivalent load of tensions applied on the pool wall is gained using elastic mechanics. The stress of the concrete section is tested when prestressing tendon is stretching and during the process of feeding water. To verify the accuracy of the measurement, calculating results are compared with the measured values by using FEM model analysis software, both are relatively approach. The paper specifically gives the differences between the measured data and theoretical data and analyzes the cause. The aim is accumulating relevant test data and providing reference for the similar project.