On the premise of the necessity of integration of cultivated land quality grades and geochemical assessment achievements and aiming at the weights determination in the integration process, the searching method was put forward to determine weights value range of cultivated land utilizations and environmental health grades by analyzing the changes of errors. Considering the influences the grade numbers on the changes of errors, the equal interval was changed and three gradation projects were designed on the premise of unchanged data base, which aimed to the integration and analysis of errors. The method proposed was verified in a county of west part in Jilin Province. The results indicated that the reasonable value range of cultivated land utilization grades was [0.7, 0.9]. The integration achievements can reflect the distribution of cultivated land quality by using different gradation projects in the integrated evaluation of the cultivated land in the researching region.