The utility model provides a be applied to phase transition heat -retaining heating system of fruit vegetables big -arch shelter culture medium, condensate outlet, sea water inlet, power plant's vapor import, heat supply pipe setup are on the condensation device of power plant, and condensate outlet and power plant's vapor import communicate, sea water inlet and heat supply pipeline intercommunication, the heat supply pipeline is planted the groove through the sea water heat supply pipeline with big -arch shelter plant species and is connected, and sea water heat supply pipe setup plants the bottom in groove at big -arch shelter plant species, heat supply pipeline, sea water heat supply pipeline, return water pipe, sea water outlet intercommunication. The condensation medium that the heat of condensation of power plant was retrieved is abundant, the cheap sea water in source. The phase change material heat supply is given to the sea water that utilizes the temperature to rise, and phase change material is in the lower part of culture medium, and the soil of direct and plant or the culture medium department of meeting maintains the temperature of soil or culture medium, and here temperature is vegetation's optimum soil temperature. The utility model discloses utilize power plant's heat of condensation to retrieve and preserve used heat through phase change material to satisfy the heat demand of fruit vegetables big -arch shelter.