  The Superconducting Quantum Computing (SQC) is one of the most promising
quantum computing techniques. The SQC requires precise control and acquisition
to operate the superconducting qubits. The ultra-precision DC source is used to
provide a DC bias for the qubit to work at its operation point. With the
development of the multi-qubit processor, to use the commercial precise DC
source device is impossible for its large volume occupation. We present our
ultra-precision DC source which is designed for SQC experiments in this paper.
The DC source contains 12 channels in 1U 19~inch crate. The performances of our
DC source strongly beat the commercial devices. The output rang is -7~V to +7~V
with 20~mA maximum output current. The Vpp of the output noise is 3~uV, and the
standard deviation is 0.497~uV. The temperature coefficient is less than
1~ppm/$^{\circ}$C in 14~V range. The primary results show that the total drift
of the output within 48h at an A/C room temperature environment is 40~uV which
equal to 2.9~ppm/48h. We are still trying to optimize the channel density and
long-term drift / stability.
