NOVELTY - A slow-released microcapsule aqueous suspension agent of herbicide sethoxydim, which is prepared by complex coacervation, comprises sethoxydim as core material; and glutin and gum arabic as wall materials. It comprises (pts.wt.): core sethoxydim (1-6), wall materials (2-8), emulsifier (1-5), antifoaming agent (1-3), curing agent (1-3), viscosity adjusting agent (3-9), and deionized water (160-200). The wall materials comprise (pts.wt.): glutin (1-4) and gum arabic (1-4) at a mass ratio of 1:1.    USE - Slow-released microcapsule aqueous suspension agent of herbicide sethoxydim, used for preventing and weeding weeds with single leaf in farm of crops with double leaves.    ADVANTAGE - The slow-released microcapsule aqueous suspension agent of herbicide sethoxydim has simple and convenient preparation technique, long-lasting slow release of ingredients with drift-proof function, high efficiency, low toxin, low cost, and safety; carries out high stabilization of the product; and is a green and environment-friendly preparation. The wall materials have no toxins and biological degradation.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method of preparing microcapsule aqueous suspension agent of herbicide sethoxydim comprising:    (A) preparing latex by providing glutin, adding deionized water to dissolve, adding sethoxydim, emulsifier, and antifoaming agent; and homogenizing and emulsifying at 2000-8000 revolutions/minute for 5-40 minutes to obtain a stable oil-in-water latex (A1);    (B) complex coacervation by providing gum arabic; adding deionized water to dissolve, obtaining aqueous solution (B1); uniformly mixing (B1) and (A1); using 10% acetic acid to regulate the pH of the mixture of (B1) and (A1) to 2.5-4.5 when temperature is at 35-55 degrees C; performing reaction under constant temperature for 40-60 minutes; and forming a reactant (C1); and    (C) solidification by cooling (C1) to 0-10 degrees C; using 10% sodium hydroxide solution to regulate pH at 8-10; adding curing agent for curing reaction for 30-60 minutes; gradually heating to 30-50 degrees C; and adding viscosity adjusting agent to obtain sethoxydim microcapsule aqueous suspension agent.