Abstract:The temperature-sensitivity of 126 isolates of Puccinia striiformis Westend. (Pst) sampled from different regions and periods was tested. The results showed that there existed a great ET50 (median effect temperature, which represents the temperature that is required to obtain 50％ of the maximum effect ) difference in Pst population tested, the average ET50 was 24.01℃ with the highest of 27.01℃ and the lowest of 18.46℃. On the whole, the Pst population sampled from warmer,lower elevation or latitude regions showed significant adaptation to warmer temperature.