对Q235B碳素结构钢和DP780高强钢进行室温拉伸试验，研究了弹性模量线的选择对屈服强度R_p0.2测量值的影响。结果表明：弹性模量线与应力-应变曲线的拟合程度，会影响弹性模量线斜率m_E的数值，从而影响屈服强度R_p0.2的测量值。对于拉伸曲线有明显屈服平台的Q235B碳素结构钢，m_E数值对R_p0.2的测量值影响不大，但对于拉伸曲线呈现连续屈服现象的DP790高强钢，m_E数值直接影响R_p0.2的测量值。

The tensile test of Q235B carbon structural steel and DP780 high strength steel at room temperature were carried out, and the effect of elastic modulus line selection on the yield strength R_p0.2 measured value was studied. The results show that the fitting degree between elastic modulus line and stress-strain curve will affected the value of elastic modulus line slope m_E, thus affected the yield strength R_p0.2 measured value. For the Q235B carbon structural steel with obvious yield platform, the accuracy of m_E value had little influence on the R_p0.2 measured value, but for the DP780 high strength steel with continuous yield phenomenon, the accuracy of m_E value directly affected the R_p0.2 measured value.