An automatic chemiluminescence magnetic enzyme immunoassay based on the high specificity of antigen and antibody was developed for rapid and quantitative determination of lead in grain. By optimizing the pre-treatment conditions and the reaction conditions of chemiluminescence magnetic enzyme immunoassay, the automatic determination of lead in rice, wheat and corn samples was realized. The detection range was 0.05~0.71 mg/kg, and the limit of detection was 0.02 mg/kg in rice and corn and 0.01 mg/kg in wheat. The recovery range was 89.2%~113.6%, and the relative standard deviations were all less than 10%. Based on the chemiluminescence immune platform, the developed method can realize eight samples simultaneous auto-detection within 30 min. Meanwhile, the automatic detection method can avoid human errors, and greatly improve the accuracy and efficiency, showing a good application prospect in the rapid quantitative detection of lead in grain.