Abstract: When smooth aluminum sleeve thickness of high voltage cables is not designed properly, wrinkling will occur during bending, which will affect product performance. In order to determine the appropriate smooth aluminum thickness, based on actual short-circuit capacity, smooth aluminum sleeve thickness was calculated according to short-circuit current calculation formula in IEC 60949:1988, and thinning design was carried out.Then external impact resistance test was conducted on thinned cables to verify the protection performance of thinned aluminum sleeve. Results showed that cable insulation of smooth aluminum sleeve with thinned thickness was not damaged after external impact resistance test, which could provide sufficient mechanical protection. Therefore, it is reasonable to use the short-circuit capacity method to design smooth aluminum sleeve thickness, and this method could effectively guide the design of the product.