Currently, most commercial microelectrodes cannot be used for in vivo or in situ measurements due to size constraints of the reference and counter electrodes. Thus, integrated miniature microelectrodes are highly desirable. In this work, an integrated needle-type microelectrode consisting of a solid Ag/AgCl reference electrode, a gold counter electrode, and a gold working microelectrode was prepared using a microfabrication technique and an electrochemical modification method. The electrochemical performance of each electrode was characterized using cyclic voltammetry. The effects of chloride ion concentration on the potential of the Ag/AgCl reference electrode were also evaluated. The results showed that the integrated microelectrode displayed high stability, reproducibility, repeatability and reliability, and that it can be used to determine constituents, profiles and functions in situ.