The invention discloses a soilless cultivation method capable of reducing nitrate of lettuce leaves, and aims to overcome the problem of the prior art that the content of nitrate of lettuce leaves is higher. The method comprises the following steps: 1, soaking and sprouting seed; 2, seeding in a manual climatic box: 1) positioning a plastic nutrition pot in which the seed is sown in the manual climatic box, the temperature in the daytime is DEG C, the intensity of illumination is 5-6 grade, the temperature at night is 15-20 DEG C, the intensity of illumination is 0 grade, the relative humidity is 70-80% RH; 2) after that the lettuce, pakchoi and cherry radish grows for true leaves for 3 pieces or 4 pieces, the height of the pea seedling is 5-6cm, preparing to transplant seedlings; 3) in order to transplant the crops at the same time, growing seedlings for the lettuce, pakchoi and cherry radish at the same batch, and growing pea seedling after 15 plus / minus 1 days; 3, transplanting seedlings; 4, preparing before fixed planting; 5, fixed planting; 6, setting cultivation environment; 7, adjusting pH and conductivity EC value of the nutrient solution in the aerosol cultivation box; 8, harvesting plants.