Abstract: Soft rock engineering is a difficult problem of rock mechanics.There are much more randomness and uncertainty in soft rock than in general rock.Therefore,it is necessary to develop reliability approach in stability analysis of surrounding rock for underground soft rock engineering.Randomness of physical and mechanical parameters of soft rock was analyzed in this paper.According to the feature of underground soft rock roadway of coal mine,reliability analysis equations for two types of surrounding rock,which are approximately horizontal medium and quasi continuous medium,were established under the condition of surrounding rock supported by bolt mesh arch. The case study proved that result obtained in this paper is accurate with bright future of application.