In view of the situation that the bias current of voltage regulation, this article delivers a high-stable direct constant- current source, which can be used as the base of data collection by proportion. This article uses a general voltage regulation, eliminating the bias current by JFET operation amplifier, to eventually improve the stability of the output current. As the result of experiment, the circuit designed in this article has the character of high-stable output of 4.73mA±66.8nA.