Design and Realization of programmable DC current source with high power and high precision is important and significant for the situation required high precision DC current source. In order to achieve high precision DC current source design requirements with high output power, high stability, high precision, small ripple, small step, this article introduces a high precision programmable DC power based on STM32F103 microcontroller. This double closed-loop control system consist by hardware and software, fuzzy controller and AD / DA devices constitute the out digital loop circuit to shorten the adjustment time of the output steady current, the inner loop with PI regulator consists current series negative feedback circuit to suppress interference continuously and improve accuracy of output current. This paper devices DC voltage stabilized amplifier circuit and Darlington amplifier circuit and power amplifier circuit. Experimental results show that the output accuracy of the power supply is 2/100000, Stability reached 3/100000 and the load capacity is strong, is especially suitable for occasions with high precision requirements.