Abstract: This study was undertaken to determine the effect of sub-high temperature of daytime on photosynthesis and growth in greenhouse tomato (Lycopersicon esculentum Mill. ). Results showed that daytime sub-high temperature (35 /15℃ and 30 /15℃) decreased the net photosynthesis and biomass, the more high
temperature the more effect of tomato was suffered. Carboxylation efficiency (CE) declined while photoresp iration at sub-high temperature increased. Root growth was more affected by sub-high temperature than shoot growth. The growth course of plant and ripping of tomato fruitwere accelerated but the quality of fruitwas decreased seriously at subhigh temperature. And a long period of subhigh temperature treatment even made the plants senescence earlier.

Key words: Tomato, Sub-high temperature, Photosynthesis, Dry matter accumulation