NOVELTY - A biodegradable release chemical fertilizer having a three-dimensional grid structure, comprises bentonite, metamorphic aged grain, and chemical fertilizer. The weight ratio of bentonite: metamorphic aged grain: chemical fertilizer is 10-15:20-25:70-60. After modifying, swelling and pressing integrated processing of the bentonite, the metamorphic aged grain and the chemical fertilizer, a columned powder chemical fertilizer is formed having a diameter of 5-10 mm, a length of 8-15 mm, chemical fertilizer powder cladding ratio of 85-95%, and a thickness of 30 nm to 2 mm.    USE - The biodegradable release chemical fertilizer is used for producing grain.    ADVANTAGE - The biodegradable release chemical fertilizer is an environment-friendly non-pollution release/control chemical fertilizer.    DETAILED DESCRIPTION - A biodegradable release chemical fertilizer having a three-dimensional (3D) grid structure, comprises bentonite, metamorphic aged grain, and chemical fertilizer. The weight ratio of bentonite: metamorphic aged grain: chemical fertilizer is 10-15:20-25:70-60. After modifying, swelling and pressing integrated processing of the bentonite, the metamorphic aged grain and the chemical fertilizer, a columned powder chemical fertilizer is formed having a diameter of 5-10 mm, a length of 8-15 mm, chemical fertilizer powder cladding ratio of 85-95%, needle holes area which is more than 20 nm of a 3D grid structure surface of less than 20% of a grid structure area, and a thickness of 30 nm to 2 mm. An INDEPENDENT CLAIM is included for a method of preparing the biodegradable release chemical fertilizer, comprising:    (A) respectively crushing the bentonite and the metamorphic aged grain, riddling the crushed bentonite and metamorphic aged grain, taking out the powder having a granularity of less than 2 mm, and mixing the powders in a weight ratio of 35-40:65-60;    (B) strongly mixing the obtained powder in an agitator tank, while inletting dry saturated steam having a pressure of 0.5-0.7 MPa and no condensed water at 150-170 degrees C, and carrying out modification processing;    (C) mixing the modified matter and the chemical fertilizer in a weight ratio of 30-40:70-60, in a combined action of a rotating screw of a bulking machine (i.e., a two-screw pump push-type bulking machine) and a die head, and pressing and forming the mixture into the 3D grid structure;    (D) crushing the expanded matter into powder having a length of 8-10 mm, and then spreading oil (0.5-1 wt.%) on a surface of the powder; and    (E) sending the material to an extruding granulator (i.e., a flat die or ring modules granulator), producing into the biodegradable columned powder release chemical fertilizer having a diameter of 5-10 mm, and forming a compact protective layer on a surface of the chemical fertilizer powder.