Abstract: Through fixed-trees observation, it was found that the development of cones and seeds are not synchronous. The cone diameter has come to the max-value in June; the increment of volume and weight of cones mainly happen before early September; the peak period of increment of seeds is from June to August, and Sept. to middle-October are even increment stage of seed weight, there is no increment afterwords; the quality of seeds including the weight of one-thousand seeds, germination percentage and vigour of seeds are worst before early Sept., medium in mid-Sept, to mid-Oct. and best in late October; the nutrient contents of cone are decrease from July to early November but the nutrient of seed are contrary, to which the increment is one-fourth from middle-Sept. to early Nov.. For determing the cone collection period accurately, two supplementary standards were recommended, that are: the moisture content of cones lower than 66% and that of seeds lower than 40%, the relative density lower than 0.95g/cm3.