The paper designs a new highprecision digital controlled alternating constantcurrent source system (ACCS), which is based on direct digital synthesis techniques. The system consists of the low frequency sine signal generator(SSG) and the constantcurrent circuits, in which SSG builds on STM32 Microprocessor and the constantcurrent circuits designs is in use of feedback based on power amplifying circuit, in order to achieve high output precision and high amplitude stability. The results show that the new ACCS can provide output current with controlled amplitude, frequency, phase, the output length, with characteristics of higher stability and precision, as well as lower noise.