Abstract: In order to study the limiting factors affecting the conversion efficiency of bolt prestress in underground coal mine roadway, six groups of bolt pre-tightening torque and pre-stress conversion tests were carried out in a mine roadway. About the transformation efficiency of anchor prestressing, the greater the deflection angle of anchor installation, the lower the transformation efficiency of anchor prestressing; the strength of coal and rock strata supported by anchor limits the value of anchor prestressing; the higher the strength of coal and rock mass, the greater the value of anchor prestressing. The research results can provide reference for the design of bolt prestress parameters in coal mining roadway.