NOVELTY - Method for preparing organic fertilizer involves (a) treating rapeseed rod using calcium hydroxide, (b) neutralizing treated rapeseed using humic acid, (c) adding crushed water hyacinth, shell powder and animal manure to neutralized rapeseed, mixing mixture, adding fermenting agent to mixture and fermenting mixture, (d) adding earthworms to stacked material and culturing earthworms, (e) separating earthworms from fermented material, and (f) adding neem leaves, Blumea balsamifera, rapeseed cake to earthworm manure, mixing mixture and fermenting mixture.    USE - The method is useful for preparing organic fertilizer for rapeseed (claimed).    ADVANTAGE - The method enables to prepare organic fertilizer which, promotes soil granule structure, increases soil permeability, soil fertility and water retention capacity of soil, facilitates breeding of microorganism in soil, hence increases soil to absorb and store maximum nutrients, allows soil to contact with air, solves problem of land compaction, provides nutrients required for growth of rapeseed plant, and enables soil to remain unchanged hence suitable for continuous cultivation of rapeseed.    DETAILED DESCRIPTION - Method for preparing organic fertilizer involves (a) weighing 50-100 parts crushed rapeseed rod, adding 10-30% calcium hydroxide to weighed rapeseed rod, and allowing rapeseed to react with calcium hydroxide for 2-4 days, (b) adding 5-20 parts humic acid to treated rapeseed obtained in the step (a) for adjusting pH between 6.5-7.5, (c) adding 30-50 parts crushed water hyacinth, 10-20 parts shell powder, and 30-40 parts animal manure to neutralized rapeseed obtained in the step (b), mixing mixture, adding 1-3 parts fermenting agent to mixture, stacking mixture and fermenting stacked mixture for 15-20 days, (d) spreading fermented material obtained in the step (c) until the fermented material reaches room temperature, stacking fermented material into thickness of 20-30 cm and width of 1-2 m, adding 0.5-30000 earthworms/m2 stacked material, maintaining stacked material at 20-26 degrees C and spraying soybean residue (every day) for 20-30 days, and culturing earthworms for 3-7 days, (e) separating earthworms from fermented material to obtain earthworm manure, and (f) adding 5-10 parts neem leaves, 2-5 parts Blumea balsamifera, 5-20 parts rapeseed cake to earthworm manure, mixing mixture and fermenting mixture for 10-20 days.