The effects of shading on ecology, physiology and biochemistry of Oolong tea by covering with black shading net in relative tea field in summer season were investigated by the authors. Results showed that in compared with control, the average temperature of daytime, maximum temperature, temperature difference and the relative humidity difference in plucking table of tea plant had been decreased remarkably, while the relative humidity of daytime and the daily minimum relative humidity in plucking table of tea plant in the shading treatment were remarkably increased. In compared with control, moisture content of shoots with one bud and three-leaves in the treatment of shading in summer and hot summer day was increased by 4.57％~6.47％ and 2.24％~2.78％ respectively. The content of total chlorophyll in leaves of the tea shoot in summer and hot summer day were respectively increased by 41.70％~48.92％and 52.38％~91.06％over the control. Similarly, chlorophyll a by 38.96％~47.25％ and 50.94％~72.52％,while chlorophyll b by 43.83％~54.58％and 67.98％~155.81％ were increased. Whereas the ratio of chlorophyll a and b was decreased by 0.1042~0.1868 and 1.10~3.54 respectively. After shading, the leaf epidermis, cuticle, palisade tissue, spongy tissue was thinned, while the lamina area was decreased, and the ratio of palisade tissue to spongy tissue was decreased. After shading, the contents of tea polyphenols, crude cellulose and caffeine in fresh leaves are all obviously reduced, while the contents of amino acid in fresh leaves are obviously increased. It was regarded that moderate shading could improve the quality and the yield of Oolong tea.