对B250P1低合金钢板在室温条件下进行了准静态和动态拉伸试验，应变率范围为0.003~600 s-1，研究了应变率对该低合金钢动态力学行为的影响,并建立了其本构模型。结果表明：B250P1低合金钢的屈服强度、抗拉强度和流变应力均随着应变率的增加而增大，具有明显的应变率效应；基于JC本构方程给出了B250P1低合金钢本构模型参数的确定方法，经过两次修正，使误差精度提高接近40%，最大误差不超过8%，并且扩大了应变率的适用范围；修正后的JC本构方程可以很好地预测不同应变率下B250P1低合金钢的流变应力，更好地满足工程开发应用的需要。

Quasi-static and dynamic tensile tests were conducted to B250P1 low alloy steel sheet at room temperature with strain rate range of 0.003-600 s-1. The effect of strain rate on the dynamic mechanical behavior of the steel was studied, and its constitutive model was established. The results indicate that the yield strength, tensile strength and flow stress of the B250P1 low alloy steel all increased with the increase of strain rate, and the strain rate effect was obviously performed. The constitutive model parameter determination method for B250P1 low alloy steel was given based on JC constitutive equation. After two times of modification，the error accuracy was improved nearly by 40%, the maximum error was less than 8%, and the applicable range of strain rate was expanded. According to the modified JC constitutive equation, the flow stress of B250P1 low alloy steel under different strain rates could be predicted well, and it could better satisfy the needs of engineering applications.