采用单点法和线性回归法对金属材料塑性应变比r值进行测量和计算。结果表明：低应变下计算得到的r值不能真实反映试样的力学性能；对于均匀塑性应变材料，采用单点法、线性回归法均可准确地计算其r值；线性回归后得到的直线是否强制通过坐标原点测得的结果差异并不明显；r值测量中平行段长度不应接近标距，从而避免造成不均匀塑性应变。

The plastic strain ratio r value of metal materials was measured and calculated by using single pont method and linear regression method. The results show that the r value is calculated under low strain can not truly reflect the mechanical properties of samples. For uniform plastic strain materials, the r value can be calculated accurately by using single point method and linear regression method. Whether the straight line obtained after linear regression is forced to pass through the coordinate origin or not the difference of results is not obvious.The parallel section length should not be close to the gauge distance to avoid the non-uniform plastic strain during r value measurement.