The utility model discloses a high accuracy and rapid speed measurement circuit of wide range current in a power system. The circuit comprises a current transformer, a signal conditioning circuit, a limiter, an A/D converter and a CPU, wherein the current transformer, the signal conditioning circuit, the limiter, the A/D converter and the CPU are sequentially connected. The signal conditioning circuit comprises a preamplifier, a main amplifier and a self-adaptive amplifier, wherein the preamplifier, the main amplifier and the self-adaptive amplifier are sequentially connected. The preamplifier is connected with the current transformer. The self-adaptive amplifier is connected with the limiter. A node between the main amplifier and the self-adaptive amplifier is connected with three branches. Each branch is provided with an average extraction circuit and a voltage comparator, wherein the average extraction circuit and the voltage comparator are sequentially connected. The average extraction circuit is connected with the input end of the self-adaptive amplifier. The voltage comparator is connected with a multiway switch through a first level converter. The circuit has an automatic level discrimination and coding circuit of multiple levels of voltage comparators, can automatically select appropriate feedback resistance and magnification factor for the amplifiers, can improve the measurement accuracy of a wide range current signal, and at the same time has rapid measurement speed.