Abstract: Basing on the theory of stress-strength interference in reliability, the reliability digital simulation software of the mechanical parts, RESI, is designed by means of the numerical method and the simulation technique. The RESI software runs in micro-computers, which can be used to calculate or simulate the reliability for many distribution status of the stress and strength random varables. It has a lots of advantages, such as the complete functions of menu, the friendly man-machine interfact, the results displaying with graph, as well as the operating simply. Several results of the reliability digital simulation in engineering problems are given.

Key words: Digital simulation, Mechanical part, Reliability, Software design, Key words: cantilever, lightweight, variable cross-section