For the underground tunnel, current stability analysis methods usually have such limitations as being empirical as well as having discrepancy in evaluation criteria. In order to calculate the stability of underground tunnels with unified models and evaluation criteria, the concept of acceleration calculation is introduced into the stability analysis of underground tunnels, and a tunnel stability analysis method based on it has been put forward. Example shows that the calculated results of acceleration have the same trend with those of the point safety factor, and the proposed method is more suitable to reflect the overall stability of tunnel surrounding rock than the point safety factor. Additionally, by drawing the contour of acceleration and acceleration factor, the stability of surrounding rock and its spatial distribution characteristics can be plainly illustrated. This explicit method can be easily achieved with a uniform mode and an evaluation criterion both for tunnel and slope, so as to solve the problem of tunnel stability evaluation which is usually difficult to be handled by traditional methods.