Based on the stream characteristics of the Lancang river, we establish the generalized model test about the scour depth of the groyne head of the mountainous river. According to the long-duration equilibrium scour experiments, we analyze the influential factors of the scour depth around groyne heads. Based on the test data of the generalized model, we set up the calculation formula for the scour depth of a spur dike with velocity v as the main parameters, which is proved more reasonable after comparing with other formulas, and tested by scour depth material of the natural river, showing that the calculated values are in accordance with measured values. The research offers a reference for ensuring the embedded depth of spur dikes and accumulates experience for regulating others rivers of the same type.