Abstract: Scientific evaluation of the risk of gushing water from coal seam floor is of great significance to mine safety production. Based on Lawrence risk formula, a modified model of water bursting coefficient which can reflect the coupling relationship of multiple factors of floor gushing water is derived mathematically in this paper. Taking Xin'an Coal Mine as an example, the modified model of water bursting coefficient suitable for the mine was fitted by using multiple linear regression. The model was applied to evaluate the risk of Ordovician limestone gushing water from the floor of No. 2₁ coal seam in Xin'an Coal Mine, and the water bursting coefficient model was used for comparative evaluation. The results show that the modified model of water bursting coefficient is more reliable. The research has realized the exploratory modification of the water bursting coefficient model, which has certain theoretical and practical significance.