The invention discloses a potato organic fertilizer used in summer, which comprises the following components by mass fraction: 3-5 parts of carbon, 3-5 parts of phosphorus, 3-5 parts of potassium, 1-4parts of boron, 1-4 parts of iron, 0.5-2 parts of manganese, 1-4 parts of zinc, 1-4 parts of magnesium, 3-6 parts of humic acid, 0.5-2 parts of amino acid, 1-5 parts of a water retention agent, and 60-70 parts of magnesium sulfate heptahydrate. The novel potato organic fertilizer can effectively increase the potato yield and has a certain water retention function.