The invention provides a high-precision controllable constant-current source with output isolation characteristics. The high-precision controllable constant current-source includes a constant-current source voltage setting circuit, an isolating circuit, a constant-current source current setting circuit and a constant-current source current locking circuit, wherein the constant-current source voltage setting circuit is used for constant-current source reference voltage acquisition and setting, the isolating circuit is used for switch control and access isolation, and the constant-current source current setting circuit is used for current setting. The constant-current source voltage setting circuit is used for setting reference voltage for the whole constant-current source so as to control the constant-current output of the constant-current source; the set voltage passes through the isolating circuit and acts on the constant-current source current setting circuit to generate constant current, and the constant current passes through the constant-current source current locking circuit and then achieves constant-current output through loading.