This standard specifies a specific method for measuring the diameter of rabbit hair fibers using the projection Microscope method, which is suitable for the diameter measurement of rabbit hair fibers. By magnifying the outline of rabbit hair fibers and projecting them on the screen, measure the fiber diameter with a wedge ruler and calculate the average value. The standard also covers the requirements of sampling, humidity adjustment and test atmospheric conditions of the specimen, providing a unified test method and specification for the quality control and testing of rabbit hair fibers.