This study applied grey system theory to analyze the relationship between eight agronomic characters including plant height, leaf fresh weight, leaf dry weight, leaf water content, internodes number of dead-leaf stalk, internodes number of green-leaf stalk, juice brix of dead-leaf stalk and juice brix of green-leaf stalk, and the maturity of sugarcane. The contribution degrees of agronomic characters, indicated by grey order, to maturity of sugarcane were: juice brix of green-leaf stalk>leaf dry weight>juice brix of dead-leaf stalk>plant height>internodes number of green-leaf stalk>leaf fresh weight>leaf water content>internodes number of dead-leaf stalk. Therefore, the juice brix of green-leaf stalk and dead-leaf stalk, leaf dry weight and plant height were the most critical characters to the maturity of sugarcane. The result based on grey relational analysis might be used as a valuable reference on the field management of sugarcane.