Energy efficient and stable power supply is the core of most electronic products. DC electronic load is essential equipment to calibrate the DC regulated power supply. with the development of power industry towards to diversification and complication, the electronic load equipment for testing power supply is put forward higher requirements. Quality of electronic load equipment is mainly reflected in three aspects, measurement accuracy, completeness of measuring project and richness of load characteristic. In the paper, the high power and constant current DC electronic load is designed. Two pieces of D/A converter are used to constitute the 20 D/A conversion unit, to realize the minimum resolution of 0.045 mV. Four magnetic rings of high permeability and magnetic properties consistency, and the corresponding processing unit circuit compose the current sampling unit, which solve a key problem and difficulty of high precision and large current test. The three groups of 600 W power modules in parallel to realize the function of 1800 W power constant current. The electronic load has the 0 ~ 300A constant current characteristic, uncertainty of measurement is 1×10-4, and the maximum load voltage is 5V. After testing, every specifications have reached the design requirements. The load is mainly used for the metrology of DC regulated power supply.