The invention discloses instant green tea powder full of juice and a preparation method of the instant green tea powder. The instant green tea powder is prepared from the following raw materials in parts by weight: 100-200 parts of a green tea, 10-30 parts of reed rhizomes, 20-50 parts of snow pears, 15-30 parts of water chestnuts, 10-25 parts of fresh lotus roots, 5-20 parts of radix ophiopogonis, 3-5 parts of Chinese yam, 2-4 parts of fleeceflower roots, 3-7 parts of Chinese wolfberry fruits, 1-3 parts of sagittaria sagittifolia, 4-8 parts of mulberry leaves, 8-13 parts of beta-cyclodextrin, 15-25 parts of maltitol, and 5-10 parts of citric acid. The preparation method of the instant green tea powder comprises the following steps of selection of raw materials, leaching with enzymes by an ultrasonic method, coarse filtration, film filtration, reverse osmosis film concentration, activated carbon absorption, squeezing filtration, debitterizing allocation, and microwave vacuum combined drying. The instant green tea powder is simple to prepare, has the efficacies of nourishing the lung, moistening dryness, dissipating dampness, eliminating phlegm, clearing away heart fire, relieving restlessness, reinforcing the spleen, the lung and the kidney and the like, and is small in size, and convenient to brew and drink. Through the vacuum combined drying technique, the quality is good, and the drinking cost is low. Through leaching with enzymes by the ultrasonic method, the yield of products is the highest, and the instant green tea powder is clear and bright.