Abstract: 27SiMn hot-rolled seamless pipe is the common raw material of hydraulic support cylinder for mining, Generally, it is not used directly in the hot rolling state and needs to be used after heat treatment. When the steel was hot rolled, it easily oxidized with oxygen and water in the high temperature air, forming a layer of oxide skin on the surface of the pipe. In this paper, the mechanical properties of two kinds of thick-walled 27SiMn hot-rolled seamless pipe samples after heat treatment are analyzed, and the results of the influence of oxide skin are obtained. The influence degree of the oxide on its mechanical properties is verified. The test results provide a reference for the application research of hydraulic support cylinder materials in coal machine industry.