Abstract: In order to illustrate correlation among various basic traits such as industrial components，physical thermal characteristics and elements，and to make a comprehensive evaluation of different crops straw，principal component analysis were carried out，using rice，corn and cotton as raw materials.Results showed that the first four principal component factors could explain 84.29% of crop straw traits.Contribution rate of the first four principal components were 41.27%，21.73%，12.93% and 21.73% respectively.With results of principal component analysis，a comprehensive evaluation of rice，corn and cotton samples were established.