In order to elucidate the influence of different altitudes to starch biosynthesis, we compared the ultrastructure of leaves and the starch contents as well as the expression of several key genes related to starch biosynthesis in Yun87 at different development stages. The results showed that on the 35 d and 50 d after transplanting, the starch content and the expression level of granule-bound starch synthase I(GBSSI)were little higher in the high altitude than those in the low altitude. But no obvious difference was found in the ultrastructure of leaves among different altitudes. From the 65 d to 95 d, starch contents showed sharp increase trend. Simultaneously, chloroplasts gradually changed with rapid enlarging and increasing of the accumulated starch granules. Correspondingly, during this period, the starch content and the expression level of GBSSI and starch branching enzyme(SBE)were higher in the low altitude than those in the high altitude. Especially, on the 95 d, chloroplasts had fully degraded, began to degrade and were still keep intact in high, middle and low altitude respectively. These results indicated that in early developing period, the higher the altitudes, the more the starch contents, but in the later developing period, it was quite the opposite.