In order to identify the influencing factors of cyclic operation time of mountain tunnel excavation constructed by drilling and blasting method and reasonably predict the construction period, on the basis of field investigation, mathematical statistics and theoretical analysis methods are used to deduce the operation time estimation formulas of drilling, charging and blasting, slag discharge, erection and wet spraying, in addition, the rational allocation of machinery in slag discharge and wet spraying processes with high mechanization level is studied. Research results show that the cyclic excavation footage of tunnel directly affects the operation time of five processes, the cyclic operation time of drilling and erection process is also closely related to the grade of surrounding rock, and the cyclic operation time of slag discharge and wet spraying process is related to the number of machinery configuration; The optimal allocation of machinery in the slag discharge and wet spraying processes will increase with the increase of the cumulative excavation footage of the tunnel; In order to facilitate the application of project managers, relevant software is developed based on C# language. The software has three functions: collection of basic information of construction cycle, calculation of mechanical supporting quantity and estimation of excavation operation time. It can realize the goal of remote monitoring of construction progress and predictable arrangement of personnel and machinery by managers, and is conducive to scientific and efficient tunnel construction, improve construction efficiency and shorten construction period.