The invention relates to the technical field of silkworm breeding, and discloses an ultra-low-cost artificial feed for silkworms and a preparation method and use method thereof. The preparation methodcomprises the following steps: kneading fresh and tender crushed mulberry twig pulp, freshly-squeezed lemon juice, soybean meal, flour, cane sugar, agar powder and inorganic salt into a dough-shapedmixture, extruding the mixture into strip-shaped artificial feed by an extruder, and laying the feed on a silkworm rearing bed for silkworm rearing. The fresh and tender crushed mulberry twig pulp isused for replacing mulberry leaf powder, the freshly-squeezed lemon juice is used for replacing a preservative, the soybean meal and other raw materials are added to prepare the artificial feed on site, heating and drying are not needed during preparation, the raw material and processing costs of the artificial feed are greatly reduced, and vitamins, food calling components and other nutrient substances in mulberry twigs and leaves cannot be damaged by high temperature; the tender mulberry twigs provide cellulose for the artificial feed, so that the feeding habit, main nutrients and physiological growth requirements of silkworms are met; and an atomization humidifier is used for humidifying silkworm breeding rooms, the problem that silkworms cannot eat due to the fact that artificial feedbecomes hard after moisture is evaporated is avoided, the input amount is reduced, and the cost is further reduced.