The circular test is a non-destructive method for quantifying leather softness and has been published in the 77th issue of JSLTC magazine. The softness of leather is one of the important characteristics for judging leather, but the characteristics of such materials are usually not objectively evaluated through subjective feelings. The establishment of circular testing closely corresponds to subjective evaluation. The softness test of the physical property tester (physical analyzer, texture analyzer) belongs to empirical measurement, which measures the energy loss and deformation during a single cycle test of the "ring-shaped" leather sample. Bend the long leather sample into a circular shape, press it down to the set displacement, and then release the pressure at a constant rate. The energy required for compression and decompression, as well as the maximum peak force and elasticity, can be obtained. Elasticity is the ratio of compressive force to compressive force.