Abstract: Effect of the time length of vernalization on the physiological and biochemical properties of various pea plants was investigated. Four different pea varieties were vernalizedat 4℃ for 0,6,12, and 18 ds after sprouting.The pea leaves were sampled 10 ds after growth for measurements on theprotective enzyme activities, MDA, and soluble protein content. The results showed that, as compared with control, the longer the vernalization was, the higher the activities of protective enzymes (i.e., peroxidase, superoxide dismutase, and catalase) in the leaves of the plant. The enzymatic acitivities peaked with a 12 d vernalization, and began to decline afterward. During the same period of time, the MDA content in the leaves increased slowly initially followed by a rapid rise on the 12th day.The soluble proteins in leaves increased at first, but varied after 12 d vernalization. Statistically at P0.05, these results were significantly different.