Abstract: 【Objective】The objective was to study the application effect of rational compounding of plant regulator in liquid fertilizer on sweet corn, and provide data support for the development of multifunctional liquid fertilizer. 【Methods】 In this experiment, sweet corn was used as the test material. The complex formulation of plant regulators such as brassinolide (BR), amine fresh ester (DA-6), biochemical fulvic acid (BFA) and liquid fertilizer were conducted under the condition of drip irrigation in the field. The effects of fertilizer complex on dry matter accumulation and nutrient absorption, and different plant regulators on the nutrition using efficiency of liquid fertilizer in different growth stages of sweet corn were compared.【Results】Three plant regulators had no effect on the growth process of sweet corn. The combination of liquid fertilizer and suitable concentration of plant regulators could significantly increase the dry matter accumulation of stem and leaf of sweet corn. The cumulative amount of 9.45%BFA+1 000 mg/kg DA-6 in the jointing and harvesting stages were increased by 58.8% and 95.3% compared to the single application of liquid fertilizer. At the jointing stage, the nitrogen contents of stems and leaves were the highest under the treatment with 10 mg/kg BR, and the highest contents of phosphorus and potassium were obtained under the treatment with 4 000 mg/kg DA- 6. At tasseling stage, the highest levels of nitrogen, phosphorus and potassium in stems and leaves were obtained under 4 000 mg/kg DA-6 treatment, no fertilizer treatment(control) and 4% BFA treatment, respectively. The stems and leaves had the highest nitrogen and potassium contents under 2% BFA treatment during harvest stage, and CK treatment had the highest phosphorus content. Plant regulators could promote the utilization efficiency of fertilizers. The treatment of 4 000 mg/kg DA-6 could increase the utilization efficiency of nitrogen, phosphorus and potassium fertilizers by 83.4%, 105.4% and 81.3%. The combination of liquid fertilizer and plant regulator could promote the yield increase of sweet corn ear. Obviously, the BFA treatment performance was the best. When the concentration of BFA was 200 mg/kg, the yield increase was 14.36%, which was the best among all treatments. 【Conclusion】The plant regulators such as BR, DA-6 and BFA compounded into liquid fertilizers could promote the growth of sweet corn. Continuous optimization of the ratios of plant regulators in liquid fertilizers has a good application prospect in modern agricultural production.