Abstract: The finite element method was applied to analyze the factors influencing the shear modulus test results with the current press-shear test method in order to verify this test method's applicability to sandwich construction with a high shear modulus. The results show that the bending deflection of the loading plate's loading end decreases the accuracy of the test results , especially to those with the high shear modulus. The test errors will exceed 6 % when the sandwich construction's modulus is over 100 MPa. Based on the study of the current test system parameters , an improved press-shear method was put forward : reducing the bending deflection of the loading plate's loading end by improving the loading method. This new test method covers the determination of the shear modulus of sandwich construction whose shear modulus is lower than 500 MPa , with a test error less than 3 %. The improved test method also reduces the sensitivity of test results to fixture dimension parameters variations , and improves the test reliability.