Taking the granite residual soil layer and fully weathered layer in Longchuan County, Guangdong Province as research objects, the shear strength under different water content conditions was studied by in-situ portable shear and drilling shear tests as well as in-situ rapid shear tests of remolded samples. The results show that the shear strength of both the granite residual soil layer and the completely weathered layer decreases with the increase of water content. The shear strength obtained from in-situ prototype test of residual soil layer is higher than that of laboratory remolded sample, and the main reason for the difference is that there is no longer strong structural connection between the particles of the remolded sample; The cohesion obtained from in-situ test of fully weathered layer is larger than that obtained from laboratory test, but the internal friction angle of the two tests is close to the same. The difference between in-situ and in-situ test results is not only related to the weak structural connection of the remolded samples, but also to the different shear boundary conditions and stress states. The shallow surface layer of granite, whether residual soil layer or completely weathered layer, has strong structural characteristics. Laboratory remolding test results often fail to reflect the shear strength of soil, and the shear strength obtained from indoor remolded soil test is low.