An organic fertilizer composition which can be used as organic compost, and a method for preparing the composition. The organic fertilizer composition can be used as compost alone or together with well-known compost. The organic fertilizer composition is prepared by: a culturing step of mixing either grape sugar, starch syrup, brown sugar, or molasses, or a mixture thereof with plant leaves selected from among those of grass, vegetables, or herbs, or a mixture thereof, adding salt to the resultant mixture to obtain a first fermented mixture, and culturing the first fermented mixture at a temperature of 20 to 60° C. for 24 hours to 1 year； a propagation step of mixing together the first fermented mixture, water, and either grape sugar, starch syrup, brown sugar, or molasses, or a mixture thereof, adding salt to the resultant mixture to obtain a second fermented mixture, and propagating the second fermented mixture at a temperature of 20 to 40° C.； and a mass propagation step of mixing together the second fermented mixture, water, and either grape sugar, starch syrup, brown sugar, or molasses, or a mixture thereof, adding salt to the resultant mixture to obtain a third fermented mixture, and mass-propagating the third fermented mixture at a temperature of 20 to 40° C. for 1 to 12 hours, wherein said mass propagation step is optional. The organic fertilizer composition can be variously used as animal feed, a soil conditioner, a water quality improvement agent, livestock feed, a malodor scavenger, etc.
