Abstract: By exploring the significant relationship between the environment fectors and the oxygen content of nutrient solution in NFT system, some suggestion a bout engineering design of the NFT system are offered to improve oxygen supply to roots. For instances:· Enlarging the volume of solution tank properly;· Attaching the sprinkling device of circulating solution;· Enlarging the tunnel of bed properly.Using the cold underground water to make up the nutrient solution in the tank, or reducing the greenhouse temperature in summer.