A series of tensile and load relaxation behaviors in B2 type β-CuZn alloy have been examined to clarify the strain rate & the temperature dependence of yield stress anomaly. As strain rate increased, the anomalous peak moved to a higher stress and temperature region. The anomalous yielding region below peak temperature (Tp) revealed slightly positive strain rate dependence, while the region above Tp showed considerably positive strain rate dependence. Based on the different tendency of temperature and strain rate dependence of anomalous yielding, two types of deformation modes were suggested and incorporated into the yield stress vs. temperature curve analysis, which was in accord well with the experimental results. The less sensitive strain rate dependence of yield stress anomaly indicated that the yield stress anomalous behavior in β-CuZn alloy mainly seemed to be attributed to the vacancy hardening.