The frost injury is studied by means of the artificial frost-box with the temperature of -1—1℃. The slow radiative cooling process in the frost night are simulated with the thawing rates of 0.3℃/10min and 1.6℃/10min, respectively. It was shown that the severity of frost injury is affected by variety of crop, freezing temperature, freezing process and thawing rate. Under some conditions the frozen tissue may be recovered by means of slow thaw, but, under otherwise conditions it may not. For the varieties of crops with different frost tolerance, the focus of attention to prevention of frost damage should be distinct.