In order to solve the problems such as roof instability or insufficient production capacity caused by unreasonable value of stope structure parameters. Taking an iron ore mine in Hebei Province as the background, how to adjust and obtain the ideal stope structure parameters and their sensitivity are studied. Firstly, in order to obtain the rock mass quality information, the rock mass quality survey is carried out on the northern rock mass, and the width and length of the stope are preliminarily determined by the extended Mathews stability diagram method with stable probability. Then, FLAC 3D numerical simulation is used to explore the deformation law of the maximum subsidence of stope roof with the change of structural parameters, and the prediction model of the subsidence of stope roof is built in combination with the response surface method, and the sensitivity of the factors affecting the subsidence of stope roof and its interaction relationship are proved. Finally, considering the safety and block size, the stope structure parameters of the north stope of the ore body are optimized, and the industrial test is carried out to verify the rationality of the results. The conclusions are as follows: the overall rating of the northern rock mass is grade Ⅴ and the quality is poor; The sensitivity of stope roof settlement to each parameter is as follows: stope width > stope length > stope height; The optimal stope structure parameters of the ore body are 12m wide, 36m long and 60m high, and the mined-out area contour is relatively flat and can maintain stability. The results show that the response surface method is suitable for the spatial design of underground stope, and has certain guiding significance for the adjustment of stope structural parameters in rock mass in the same area. The stability of industrial test is good, and the optimization results are reasonable. The research results can provide theoretical basis for how to adjust reasonable stope structural parameters and correctly coordinate safety and production capacity.