Abstract: As uncertainties of inherent factors (such as loads, environment and material properties) always exist during driving axle's lifetime, a time-dependent model incorporating such uncertainties was established based on stochastic differential equation theory. Combined with the distribution parameters of multiple random variables, the time-dependent design method of driving axle parts under uncertainties in stress and strength was presented and it was illustrated by taking the shaft's time-dependent design as an example. It is indicated that this method, with good prospects, can make dynamic security evaluation of reliability for driving axle products. The shaft's time-dependent design reveals the impact of time scale on the design. Under the premise of meeting the performance requirements, it could effectively reduce the size of parts.