Abstract: The seedling height and ground diameter of 5 months and 10 months seedlings of Eucalyptus globules and E.maideni were determined, respectively.The growth difference of the same age seedlings was analyzed in the same species.The selection criteria for super seedlings of E.globules and E.maiden were severally researched through standard deviation method.The results show that it is equipped with the basis for the growth of super seedling selection of sample seedlings, furthermore, the variable coefficients of seedling height are greater than that of ground diameter at the same age in the same species seedlings and there are significant positive correlation between seedling height and ground diameter at the same age in the same species seedlings.The super seedling′s selection criteria of sample seedlings is the average seedling height plus 2 times standard deviation.The appropriate seedling age of super seedling′s selection about E.globules is 5 months and that of E.maiden is10 months.The super seedling′s selection effect is very obvious because these selected super seedlings have a large incremental advantage.There is a significant positive correlation about height increment between the 5 months′ and 10 months′ seedling age of sample seedlings, so early selection of seedlings was effective and feasible about E.globules and E.maiden.