Abstract: In order to get the cutting mechanical parameters of cotton stalk in low stubble condition, microprocessor controlled electronic universal testing machine (WDW-5E) was used to study the shear properties of cotton stalk in different harvest time and moisture contents. The results indicate that shear strength of cotton stalk is closely related to moisture contents. The shear strength and the work by shear force are lower when the moisture contents of cotton stalk is in range of 30%–50%. The shear strength is higher when the moisture content is exorbitant or too low and it reaches the peak value when the moisture content is around 60%. The shear strength of cotton stalk is in range of 0.6–1.8 MPa and the work of shear force is 1–4.5 Nm. So it can be identified that a period begin at late December is the best harvest time for cotton stalk. It can save 16.4% of the shear power.