To studythe effect of prestress on the warping stress of curved box girder with corrugated steel webs， prestressed equivalent load is applied to the calculation of curved box girder with corr ugaated steel webs.By Umansky's second warping theory and the mechani-cal property of thecurved box girder with the corrugated steel webs， the torsional differen-tial equation of currv ed box girder with corrugated steel webs is established， and the con-strained torsional stress is obtained by initial parameter method.The results show that pre-stressed effect istat ken into account or not will lead to different constrained torsional stress if prestressed steelbundles a replaced asymmetrically.The comparison shows that the ratio of the torsional norrmal stress caused by the prestressed effect reaches 33%， and that of the torsional shears tressis 14.28%.The torsional effect caused by the prestressed effect in the case of asymmetric reinforcement can't be ignored.The calculation results of this paper are consistent with the finite element calculation results， which indicates that the analysis method has relatively high precision.The method can be used to improve the calculation theory of curved box girder bridge with corrugated steel webs.