The invention relates to a novel long-acting alkaline compound fertilizer and a preparation method thereof, which are applied to the field of agriculture and forestry production. The novel long-acting alkaline compound fertilizer comprises long-acting stabilizer, soil conditioner and medium or trace elements. When the long-acting alkaline compound fertilizer is prepared, urea or ammonium chloride, monoammonium phosphate or diammonium phosphate, monopotassium phosphate, potassium nitrate, chelate iron, chelate manganese, chelate copper, chelate zinc, disodium octoborate tetrahydrate, calcium magnesium powder and the like are mixed according to a certain scientific proportioning, then are added with a certain quantity of plant nutrient conditioner and the long-acting stabilizer, are sufficiently mixed with the plant nutrient conditioner and the long-acting stabilizer, and then are granulated to form the novel long-acting alkaline compound fertilizer. A production process is simple, raw materials are easy to obtain, nutrient is comprehensive, nitrogen, phosphorus, potassium and the medium or trace elements are provided for soil and plants, the utilization rate of the fertilizer is improved effective, the pH (potential of hydrogen) of the fertilizer is larger than or equal to 7, and accordingly the fertilizer is suitable for acid soil, and has the advantages of improving the soil and preserving an ecological environment.