The invention discloses a method for preparing 2-mercaptobenzothiazole, which comprises the steps of: adding carbon disulfide, aniline and sulfur into a reaction kettle; and heating the mixture, finishing a reaction under the reaction pressure of 6.8 to 9.5MPa to obtain a crude product, namely a melt, pressing the melt into a crystallizer loaded with carbon disulfide, controlling the initial temperature of the crystallization, reducing the temperature, beginning to discharge hydrogen sulfide when the material temperature in the crystallizer is reduced to be between 70 and 100 DEG C, controlling the discharge time of hydrogen sulfide to be between 20 and 60min, cooling the obtained product to be between 15 and 20 DEG C, filtering the obtained product to obtain a filter cake and carbon disulfide mother liquor, washing the filter cake for 2 to 5 times by using carbon disulfide in an amount which is 1 to 3 times mass of the filter cake, and drying the scrubbed filter cake to obtain the 2-mercaptobenzothiazole at the mass percentage concentration of over 98 percent. By the method, no 'waste water' and 'waste gas' are discharged, and asphalt-like wastes are greatly reduced. The circulation of crystallization mother liquor realizes the recycling of intermediate products, and the total yield of the process is improved to be over 94 percent.