The invention provides a tobacco stem field stacking and retting fermentation method. After tobaccos are matured and harvested, tobacco stems are collected on the spot and are broken according to a certain size; and then stacking and retting fermentation is performed on the tobacco stems by mixing the tobacco stems with water, soil, cow dung, phosphatic fertilizer, a ferment activator and lime according to proper proportions. The invention also provides a compost product produced by the tobacco stem field stacking and retting fermentation method. A using method for the compost product obtained by tobacco stem stacking and retting fermentation is characterized in that the compost product is fertilized every two crop planting periods preferably; the fermented compost product is used as a base fertilizer; and a ditch is formed, and the compost product is fertilized into the deep ditch. According to the tobacco stem field stacking and retting fermentation method, the application amount of chemical fertilizers can be reduced, a soil ecological environment is protected, the soil is improved, the soil fertility is improved, and the tobacco stem field stacking and retting fermentation method is safe and ecological. By the method, raw materials are readily available, convenient to collect, easy to operate, environmentally-friendly, sanitary and low in cost, and tobacco farmers can easily master the method; the cost is low, the expense is low, the production technology is simple ad can be easily popularized and applied in a large tobacco area; the quality of a product is stable; and the economical and ecological benefits are outstanding.