Abstract: A newly bred strain of Strelitzia reginae showed superior resistance to the cold weather in Fuzhou as compared to its parent. To quantifiably verify the observation, relative electric conductivities of the leaves and semi-lethal temperatures (LT50) of the two cultivars were determined. LT50 was calculated using a logistic equation at a temperature gradient from 0, -2, -3, -4, -5 to -6. The results showed that the conductivities significantly increased with decreasing temperature in an S-shape function. And, the LT50 of the new strain was -4.8, which was considerably lower than that of its counterpart, at -3.6.