A method for testing cutting performance of a diamond saw blade, relating to a technical field of diamond tool test, is provided, which solves problems of inaccuracy and non-uniformity existing in conventional methods for testing cutting performance of a diamond tool. The method includes steps of: (1) obtaining a set load parameter value, particularly including steps of: controlling a feed amount of the diamond saw blade; finding out a load value K corresponding to a maximum feed amount of the diamond saw blade on a cutting object; and setting M=0.70K-0.85K, wherein M is the set load parameter value; and (2) during cutting, controlling a cutting load value of the diamond saw blade to be 0.90 M-1.1 M through a servo system. Therefore, uniform three cutting elements of machine and tool, object, and feed thrust are realized, and the performance of the diamond tool is automatically and accurately measured.
