NOVELTY - Preparing o-cresol and m-cresol, comprises (i) performing hydrolysis reaction by using o-chlorotoluene and 20-25% sodium hydroxide, where the hydrolysis reaction is carried out under constant temperature and pressure; (ii) adjusting addition speed and discharging speed so as to ensure that the material remains in the tubular reactor for 120-180 minutes; (iii) cooling the material in the reaction section below 100 degrees C in the cooling section after the completion of the reaction, and then reducing the pressure to 0.1 MPa by a decompression valve; and (iv) continuously discharging the material.    USE - The method is useful for preparing o-cresol and m-cresol.    ADVANTAGE - The method shortens the production cycle, and improves the production yield by replacing the traditional tank reaction with tubular reactor; reduces labor costs, and energy consumption; produces high reaction yield of up to 95%, and product with high purity content reaching unto 99.5%; and has high safety factor, clean environment protection, and less pollution when compared to the traditional tank reaction.    DETAILED DESCRIPTION - Preparing o-cresol and m-cresol, comprises (i) performing hydrolysis reaction by using o-chlorotoluene and 20-25% sodium hydroxide as raw materials, where the hydrolysis reaction is carried out in a tubular reactor under the conditions of constant temperature and pressure, the tubular reactor is divided into a heating section, a reaction section and a cooling section, the constant pressure maintained in the tubular reactor is 25-26 MPa, the temperature of the material in the reaction section is maintained at 360-370 degrees C to perform the hydrolysis reaction, and the feed volume ratio of o-chlorotoluene and sodium hydroxide is 1:2.2; (ii) adjusting the addition speed and discharging speed so as to ensure that the material remains in the tubular reactor for 120-180 minutes; (iii) cooling the material in the reaction section below 100 degrees C in the cooling section after the completion of the reaction, and then reducing the pressure to 0.1 MPa by a decompression valve; and (iv) continuously discharging the material. The discharged materials are processed by (a) separating the material to obtain an organic phase and an inorganic phase by a separation pot, processing the inorganic phase by neutralization step, distilling the unreacted o-chlorotoluene in the organic phase, and returning to the hydrolysis step; (b) neutralizing the separated inorganic phase by adjusting the pH to 4-5 by adding 30-35% hydrochloric acid, stirring, and filtering, and then allowing the mixture to stand, and layering, pumping the upper aqueous phase into an extraction kettle, and obtaining an organic phase in the lower layer for performing distillation process; (c) pumping the aqueous phase into the extraction kettle, adding aqueous phase and trichloromethane in the volume ratio of 100:2, adding trichloromethane, stirring for 10 minutes, allowing to stand for 40 minutes, layering, pumping the organic phase in the lower layer into a distillation kettle, and removing water from the aqueous phase in the upper layer; (d) pumping the extracted organic phase into the distillation kettle, heating, and performing distillation at a vacuum degree of -0.095 Mpa to -0.1 Mpa, and the temperature of 30-50 degrees C, and collecting the organic phase after distillation; and (e) mixing the organic phases obtained in the steps (a) and (d), and then pumping into a reboiler of a rectifying tower, maintaining the degree of vacuum at -0.095 to -0.1 MPa, heating by adding a heat-conducting oil into the reboiler, sampling for laboratory test when the recovery temperature of the tower top reaches to about 130 degrees C, collecting the o-cresol extract when the o-cresol content is 99.5%, sampling for laboratory test when the temperature continues to rise, and completing the extraction process when the o-cresol content in the reboiler is less than or equal to 0.1%, carrying out cresol extraction by sampling for laboratory test when the recovery temperature of the tower top reaches to about 140 degrees C, collecting the m-cresol extract when the m-cresol content is greater than or equal to 99.5%, sampling for laboratory test when temperature continues to rise, completing the extraction process when the o-cresol content in the reboiler is less than or equal to 0.1%, extracting biphenol when the recovery temperature of the tower top rises to 180-210 degrees C, sampling for laboratory tests when the biphenol content is greater than or equal to 99.5%, collecting the biphenol extract, sampling for laboratory test when the temperature continues to rise, and completing the extraction and rectification processes when the biphenol content in the reboiler is less than or equal to 0.1%.