Abstract: In order to choose rational strength for strip-filling material, for mechanical characteristics of filling strip in room mining gob, we established numerical model, cleared filling factors affecting the carrying capacity of the body. The factors that have a greater impact on bearing capacity were arranged for orthogonal test, and neural network forecast model for calculating the filling material strength was established base on the data obtained from the orthogonal test, which had a better prediction effect. Meanwhile, the most suitable strength of filling material for engineering practice was confirmed.