Abstract: Effects of environmental temperature on the contents of chlorophyll, soluble sugars, reducing sugars, starch and proline (Pro) of the cut flower variety Jinhui of Oncidium were studied. Four day/night temperatures, i.e., 12/4℃, 20/12℃, 28/20℃ and 36/28℃, were applied on the floral plants for a same period prior to the chemical analyses. The results showed that the chlorophyll content peaked at 28/20℃, followed by 36/28℃, and reached the lowest at 12/4℃. Soluble sugars decreased in the leaves as the temperatures rose; and, in the pseudobulbs maximized at 20/12℃, followed by 12/4℃, and minimized at 36/28℃.The leaves contained more reducing sugarsat 12/4℃ or 20/12℃ than at 28/20℃ or 36/28℃; whereas, the pseudobulbs had the highest content at 20/12℃, followed by 12/4℃, and the lowest at 36/28℃. For starch, the content was high at 12/4℃ and low at 36/28℃ in the leaves or the pseudobulbs; and, it was always higher in the leaves than in the pseudobulbs. Pro contents in the leaves and the pseudobulbs were the highe stunder 36/28℃, followed by 12/4℃, and the lowest under 20/12℃ or 28/20℃. The temperature exposure at 20/12℃appeared conducive to the growth of stems and leaves. However, it delayed the starting of the lateral buds. At 36/28℃, the budding was stimulated, but the growth and robustness of the budsseemed disadvantaged. And, at 28/20℃, both lateral bud germination and pseudobulb growth were enhanced.