The invention belongs to the field of cladocerous zooplankton culture, and relates to a laboratorial breed conservation culture method of daphnia magna. By the breed conservation culture method, long-term stable growth of the daphnia magna in a system can be ensured, and regular supplementation of evaporated water is needed, but addition of additional bait is not required. After adoption of a simple experimental system for breed conservation, the operation is simple, the cost is low, the daphnia magna can grow and propagate steadily, regular field seed collection is not required, troubles of frequent artificial water change, bait feeding and impurity and waste removal in ordinary culture are avoided, and thus a purpose of simple and convenient laboratorial long-term breed conservation is achieved.