The invention relates to an accurate measuring method of friction coefficients of a pre-stressed duct, and belongs to the technical field of building construction. The method comprises the steps of threading a steel strand, mounting a driven end, mounting a driving end, stretching the driving end, stretching the driven end, solving cable separating force, and calculating the friction coefficients. With the adoption of the method, the friction test and the stretching process are basically synchronized; the driven end can be simply equipped with a dial indicator for acquiring the pressure of the corresponding end; after stretching at the driving end is finished, rest stretching can be finished at the driven end, so that the convenience is ensured, and operators are obviously decreased; in addition, the friction test processes are simplified, so that the data deviation of the friction test is obviously inhibited, and thus the measuring result is closer to an actual construction condition of engineering.