The invention discloses a soil solidifying agent, and a preparation method and a use method thereof. The soil solidifying agent is prepared from, by weight, 0.4 parts of
calcium lignin sulfonate, 0.9 parts of
sodium polycarboxylate, 1.7 parts of
lithium hydroxide, liquid aluminum dihydrogen
phosphate, illegally recycled waste
cooking oil,
sulfamic acid and
distilled water, the pH value of the soil solidifying agent is 5-9, a weight ratio of the illegally recycled waste
cooking oil to the liquid aluminum dihydrogen
phosphate is 1.5:1, and the use amount of
sulfamic acid is 1 / 2 of the total weight of the illegally recycled waste
cooking oil and the liquid aluminum dihydrogen
phosphate. The preparation method of the soil solidifying agent comprises the following steps: preparing an alkaline
neutralization solution, preparing acidic
fatty alcohol sulfide, mixing the alkaline
neutralization solution with the acidic
fatty alcohol sulfide, layering and extracting, and filtering to prepare the finished soil solidifying agent. The soil solidifying agent provided by the invention is not strong acidic or alkaline, and has the advantages of high safety, no
pollution to environment, strong compression resistance, high water stability, high freeze stability and realization of waste utilization of the illegally recycled waste cooking oil; and the preparation method of the soil solidifying agent has the advantages of low
energy consumption, no pollutants, safety and
environmental protection.