Abstract: Water equipment of plants is composed of plant transpiration and soil evaporation between plants. This experimentation not only studies the water requirement of tomato but also studies the relativity between water requirement of tomato and environment factors in solar greenhouse in different season. The experimentation comes out that in autumn-winter water equipment of tomato becomes less and less, but in winter-spring water equipment of tomato becomes more and more. In autumn-winter the total water equipment is 2098.95 m3/hm2, but in winter-spring the total water equipment is2789.25 m3/hm2. Among the environment factors, temperature and humidity each has the most powerful influence on plant transpiration and soil evaporation in winter-spring, but in autumn-winter the most powerful influence factor of environment on plant transpiration and soil evaporation are both light intensity.