The invention discloses a method for preparing and feeding a paste-state semi-wet compound feed for tachypleus trideutatus, and belongs to the field of feed production. According to the technical core, the preparation method comprises the following steps of weighing phaeodactylum tricornutum powder, beer yeast powder, nereid, scallop, mussel, lumbrukinase, shrimp head powder and other raw materials according to the formula requirement, grinding the raw materials, screening the raw materials through a 100-mesh screen, adding 40-45 percent of water into the raw materials, and conducting uniform stirring to obtain the paste-state semi-wet compound feed. According to the technical scheme of feeding, the feeding method comprises the following steps of weighing the semi-wet feed according to the general weight ratio of bred tachypleus trideutatus, piling the semi-wet feed into a small pile to attract the tachypleus trideutatus to forage. The compound feed is comprehensive and balanced in nutrition, has small energy consumption since high-temperature and pelleting treatment are not conducted, is advantageous to healthy and quick growth of tachypleus trideutatus since vitamins, amino acid, fatty acid and other bioactive ingredients in the feed are not inactivated, and has the advantages of easily available raw materials, simple process, relatively low cost, rich fragrance, good attractive effect and extremely small pollution to water body.