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The shear behavior of shotcrete-rock interface same as the bond behavior plays a significant role on shotcrete behaviour in a tunnel. The shear strength of shotcrete-rock interface is noticeably affected by high temperature in high rock temperature tunnels. However, there are limited number of studies dedicated to investigate behaviour of shotcrete-rock interface in high temperatures. Therefore, a series of direct shear tests was performed, under the normal stress of 0.5, 1.0 or 1.5 MPa, to investigate the influence of high rock temperature on the shear characteristics of shotcrete-rock interface. Shotcrete-rock samples were cured under the temperature range of 20 to 100°C and the relative humidity of 55 or 95 % before shear tests. The results show that curing temperature, relative humidity and normal stress have significant impacts on the peak shear strength, however, only the normal stress has the same impact on the residual shear strength. The peak shear strength as well as peak cohesion reaches its maximum value at 60°C curing temperature with 55 % relative humidity level, and at 80°C curing temperature when the relative humidity is 95 %. The shear stressdisplacement curve presents various shapes in the section of post-shear due to the influence of high temperature and relative humidity.

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