The invention relates to a hydrocracking method for producing chemical materials to the maximum with low cost, comprising the following steps: mixing raw oil and hydrogen gas , entering a first reaction area, sequentially contacting with hydrofining catalyst and hydrocracking catalyst, reacting under the pressure of 6.0-16.0 MPa; carrying out oil-gas separation and fractionation on the reaction products thereof to obtain liquefied gas, light naphtha fractions, heavy naphtha fractions, middle fractions and tail oil fractions; mixing the middle fractions and the hydrogen gas and enteringa second reaction area, contacting with the hydrocracking catalyst under the pressure of 1.0-5.5 MPa to react; and carrying out oil-gas separation on the reaction products thereof and entering a fractionation system . By adopting the method, heavy raw materials such as vacuum gas oil, coking gas oil and the like are treated to obtain more than 98 weight percent chemical materials. In the invention, themiddle fractions are wholly converted into the chemical materials in the low pressure condition, and low hydrogen consumption, low investment cost and low operation cost are realized.