Abstract: The length, width ,weight and seed output of the cones of Thuja sutchuenensis were analysed. No significant difference was found on length, width and dryweight of cones from two natural distribution of Thu ja sutchuenensis-Xuebaoshan and Dabashan mountains. But the effect of differentmother p lants under the same condition on thesecharacterswas significant. For the cones of Thuja sutchuenensis, the p roportion of the coneswithout seed was 7. 1%.The average p lump seed number per cone was 3. The 1 000 seed weight of Thuja sutchuenensis was lighter, only1.126 4 g. No significant difference was found for the seed number in different cones from the same mother p lant.This showed that for the same mother p lant the sexual rep roduction was in the same developmental level and conesdevelopment was nearly the same.