In power system, electronic current transformer has been used to measure current for more than one hundred years, its performance has very important significance for the normal running of the power system. As the key part of the current transformer, the special display instrument also attracts lots of scientists. A special display instrument for electronic current transformer which applies to measuring small current was proposed in this article. The instrument utilized single chip computer and analog signal process to achieve the output voltage display of electronic current transformer. Besides, the instrument adopted a specific algorithm which did not require so much time-consuming calculation, it was simple for the hardware design, ensuring the accuracy of the display instrument on the base of low-cost. Also, the instrument had buttons and reset circuitry to enable external control. After experimental verification, the special display instrument for electronic current transformer can work reliably, the measurement result can meet the 0.2 national standard.