Abstract: Uncertainties parameters of section carrying capacity calculation in emergency were analyzed. The capacity calculation method is established according to characteristics of dynamic, fuzziness, randomness and non-aftereffect property based on fuzzy Markov chain. When encountering with the special operating conditions or random interference, the state transition matrix is established by fuzzy evaluation method, and then railway network capacity is calculated in good time based on the train speed. The case study shows that the capacity calculation method based on fuzzy Markov chain was more tolerant types of uncertainties, which are fit for predicting the railway network through capacity in future period.