Abstract: The observation on the past years' seed-producing Xinjiang larch(Larix.sibirica) indicated that on the basis of biological characteristics and living environment conditions from tree abloom,the different clones existed significant difference in the seed quantity and the insect injury rate;the bearing branch age was 2-5 years,the branch was nuable to bear seeds when it was over 6 years,the most bearing age was in the 2nd year,the biggest seed set growth was 2.6~10.63 times more than 3~4 years' branch,increased the simple seed volume,and seed was fuller and quality better from lower crown to upper crown.There were great differences among the seed quantity in the differences plant density of 25-years' graft seed production.The denser was the stand of the seed trees,the smaller were the seeds produced.