The basic ideas of expressing uncertain variables with blind number were introduced. The mechanical structure time-dependent characteristics variation in stochastic process was deduced. A time-dependent reliability calculation model was built with blind number theory. The numerical method based on blind number was applied to solve this complicated computing model. A LabVIEW program was compiled, and a frame beam’s time-dependent reliability was computed. The result shows the method based on blind number is very convenient and effective in solving the complicated reliability calculation model. In this method, the structure time-dependent reliability can be predicted quickly based on the historical data.