The invention discloses a yarn elasticity difference identification method. The yarn elasticity difference identification method comprises the following steps: two different batches of yarn are wound into hanks, a hank a and a hank b are formed, and initial tension Ts of the hank a and the hank b is calculated; one end of the hank a and one end of the hank b are fixed respectively , tension is applied to the other ends in a gradient manner and is kept until a preset period of time is up, the applied tension and tension applying time to the hank a and the applied tension and tension applying time to the hank b are equal, and the length of the hank a and the length of the hank b under actions of different tension amplitudes are measured; the elasticity standard deviation SD of the hank a and the elasticity standard deviation SD of the hank b are calculated and/or the elongation rate of the hank a and the elongation rate of hank b under different tension amplitudes are calculated, and the elasticity difference of the hank a and the hank b is obtained by comparing the elasticity standard deviation SD of the hank a and the elasticity standard deviation SD of the hank b and/or drawing a tension-elongation diagram and/or drawing a tension-elongation rate diagram. The yarn elasticity difference identification method can be conveniently applied to elasticity difference test of various types of elastic core-spun yarn.