Abstract: In order to optimize the working face length of casting blast stripping system under the condition of comprehensive technology, on the basis of analyzing the coupling influence relationship between the casting blast stripping bench and the comprehensive technology system, the advancing speed of the casting blast stripping bench is determined as the restrictive factor in the comprehensive technology system under the constraints of the deepening procedure of the stripping and excavating engineering. By taking the comprehensive technology system of Heidaigou surface coal mine as the background, the influence of working face length of casting blast stripping system on the cost of comprehensive technology stripping, the transportation cost of internal exhaust and the operation efficiency of the stripping system was systematically analyzed, as well as the influence relation model was established. The minimum of the total stripping cost of comprehensive technology composed of the excavating cost and transportation cost of discontinued technology and the stripping cost of casting blast dragline technology was taken as the objective function, and the functional relationship between the total stripping cost of the comprehensive technology and the working face length of the casting blasting bench was determined. Besides, the minimum working face length of two partition, dragline system capacity, surface mine production capacity and working face length nonnegative considered was selected as constraint conditions, a constrained nonlinear programming model for the working face length of the casting blasting stripping system under the comprehensive technology conditions was constructed. According to the measured data of the comprehensive technology of the Heidaigou surface coal mine, the calculation results show: ① the comprehensive technology stripping cost and the optimal working face length increase with the increase of production capacity, and the optimal working face length is also closely related to the annual operating time affected by the annual actual rate of dragline. ② Under the current conditions of dragline actuation rate and system mining parameters, the optimal working face length to meet the production capacity requirements of 34 Mt/a should be 2.29 km, while the working face length of 2.30 km limited by the actual conditions of the existing mining area division and working conditions can meet the production capacity requirements of 34 Mt/a. ③ Under the same production capacity, the optimum working face length and the total stripping cost decrease with the increase of dragline actual operating rate.