NOVELTY - Preparing biodiesel fuel containing 60% butachlor, is claimed. The biodiesel fuel comprises 92% butachlor having 65.2 pts. wt. solid content, 16 pts. wt. sodium lauryl polyoxyethene (7) octyl sulfosuccinate diester having concentration of 62%, and 18.8 pts. wt. biodiesel.    USE - The method is useful for preparing biodiesel fuel containing 60% butachlor (claimed).    ADVANTAGE - The method has simple production procedure due to the utilization of catalyst during the esterification process of the carbon-based solid acid catalyst with oleic acid and mathanol added in cyclic manner; is economical; easily achieves industrialization; and utilizes aromatic hydrocarbon-based organic solvent during the preparation of miscible oil which reduces the environment pollution.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing biodiesel fuel containing 60% butachlor miscible oil, comprising (i) preparing a catalyst by adding p-toluenesulfonic acid and soluble starch into a beaker, dissolving with distilled water, then heating until the solution is clear and transparent, then cooling to room temperature, evaporating to thick colloid by a rotary evaporator, placing into a muffle furnace, carbonizing for 8 hours at 200 degrees C, taking out, and grinding, and then passing by 80 meshes sieve, to obtain a carbon-based solid acid catalyst; (ii) synthesizing biodiesel by sequentially adding 1 wt.% oleic acid and carbon-based solid acid catalyst into a reactor, and simultaneosuly heating in a water bath, setting the reactor water temperature to 99 degrees C, and then setting the water bath evaporator to 90 degrees C, adding methanol to start the reaction, continuously reacting for 2.5 hours, then filtering the product by a Buchner funnel, separating the carbon-based solid acid catalyst, completing the filtration process, recovering excess methanol from the filtrate by the rotary evaporator, and distilling to obtain the product; and (iii) dissolving all the above mentioned raw materials together to obtain the product.