Measurement circuit of direct current

The invention provides a measurement circuit of direct current, comprising a main circuit of the direct current to be measured. In the measurement circuit of direct current, a first conductor is connected with the main circuit in series; one end of a second conductor is connected with the first conductor; the resistance of the first conductor is less than that of the second conductor; the other end of the second conductor is respectively connected with a drain electrode of a first field effect transistor of the measurement circuit of direct current and a positive voltage input end of an operational amplifier; the other end of the first conductor is connected with a negative voltage input end of the operational amplifier of the measurement circuit of direct current; an output end of the operational amplifier is connected with a grid electrode of the first field effect transistor; a source electrode of the first field effect transistor is connected with one end of an amperemeter; and the other end of the amperemeter is connected with the ground of the measurement circuit of direct current. The invention can accurately detect high current, and has low power consumption and large scope of detected current.