Abstract: The introduction experiment for three years showed that the above ground parts of A. fruticosa and R. pseudoacacia were damaged differently coldness in the region (annual average temperature 2.5℃, Jan. average temperature -16.1℃), while the roots could safely survive the winter. The hardiness of roots had increased through three years of natural cold inducement, and LT50 values of them dropped 3.2℃ and 2.0℃ respectively. Meanwhile, the initial damage temperature also dropped 2.0℃ and 2.6℃ The chilling injury experiment demonstrated that roots had phenomenon of tissue softening and browning, accompanied with something of sweet taste. When temperature was below certain points, a Logistic equation could imitate well this chilling injury process.