Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects ofthree shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N),phosphorus (P) and potassium (K) in leaves and yield at three growth stages (early flowering (EF), peakflowering (PF) and later flowering (LF)). Shading reduced the dry weight of root and stem tissues at the EFand PF stages, but the 40% shading increased root dry weight and stem dry weight by 43.2% and 21.6%,respectively, at the LF stage. The influence of shading on the dry weight of leaves was very small at mostgrowth stages. Shading had no effects on total leaf N, P and K contents at the EF and PF stages, showingthat N, P and K absorption were regulated by the carbon assimilation at these two stages. The leaf N, Pand K contents of 40% shaded plants at the LF stage were significantly increased. There were no obviousdifferences in leaf N and K contents between 75% and 40% shading treatments, but significant difference inleaf P contents was found between them at the LF stage. Shading significantly enhanced the fruit yield of40% shaded tomato plants at the LF stage, but failed to affect the fruit yield of shaded plants at the EFstage. These showed that tomato could grow well and a better yield could be obtained if some moderateshading (i.e., 40% shading) was applied at the LF stage at summer midday.