The invention discloses a method for increasing the yield of garlic by means of modified calcium cyanamide and belongs to the field of pesticides and chemical fertilizer. According to the method, 20-60 kg of modified calcium cyanamide of 50% is applied to each mu; soil finishing is needed before application, soil is ploughed by 25-30 cm, then a rotary cultivator is adopted for soil preparation to enable soil particles to be fine and uniform and chemical agents, manure and soil to be mixed sufficiently and evenly, and soil humidity is kept to be 60-70%. By the adoption of the method, garlic growth economic character is improved, the yield increasing effect is remarkable, and the yield increasing rate reaches 22.3-89%.