Abstract: In this study, the integral bridge with various span length of 40m, 50m, 60m and 70m non-skew and skews angles of 15, 30, 45 and 60 were designed, and modeled in SAP2000 software. The parameters investigated in this analytical study were skew angle, span length and stress reduction methods. The geometric dimensions of the Integral Bridge and the loading used were in compliance with AASHTO standard specifications. Static analysis and dynamic nonlinear time history analysis were performed to assess the seismic performance of integral bridge. The analysis results in terms of shears and bending stresses, axial force and deflection were checked by allowable stress method. Extreme stresses that exceed allowable limit were reduced by using six different stress reduction methods. The propose of this study was to analyze behavior of integral, skew angle, and to reduce extreme stress of integral bridge under dynamic loading. In skew angle bridge, cross frame member stress increase greatly as skew bridge tend to rotate during a seismic event, which can cause excessive transverse movement. MSE+HLAC method was the best stress reduction method for all non-skew and skew angle bridge. According to analysis result, integral bridge maximum skew angle can be extend up to 60 and span length up to 60 m can be extended using stress reduction method under extreme seismic loading.