After cold hardening the content of free proline, hydroxyproline combined with cell wall, and glycoprotein changed obviously in wheat seedlings of strong cold resistant varieties R 025, Zhongpin 94 19, Pin 83 1, Pin 83 2, Pin 83 3, and Mironov 808. The accumulating process of proline varied in different varieties, and the correlation between proline content and cold resistance of wheat was not significant (correlation coefficient=0 3462). But both hydroxyproline and glycoprotein had a significant correlation with the cold resistance of wheat, and the correlation coefficients of them were 0 6491 and 0 7039, respectively. Two types of extensin protein, Extensin 1 and Extensin 2 were purified on a CM cellulose column, and they both had a positive relationship with the cold resistance of wheat. SDS PAGE and amino acids analysis demonstrated that Extensin 1 was a kind of hydroxyproline rich glycoprotein with a molecular weight of 28 kD, and hydroxyproline was the major component of it(32 mol%).