This manuscript gives a complete survey on commonly used reference current extraction techniques in Single-Phase Shunt Active Power Filter (SAPF). A single-phase shunt active filter usage is increased considerably over the past few years in commercial and educational buildings to improve power quality leads to achieve customer satisfaction. The performance of a shunt active power filter depends largely on the extraction of harmonic current. To reproduce the exact inverse image of harmonics currents, various reference current extraction techniques like PI control algorithm, PQ Theory, DQ Theory, and other techniques are discussed. And the primary advantages and disadvantages of power filters are compared. Eventually, the selection of DC-Link capacitor voltage and capacitance rating and filter inductance of the SAPF was expansively appraised in detail. Almost all these research work-related papers have been thoroughly examined, classified and listed for quick reference. It will offer a clear vision of the state-of-the-art investigation advances in this field and then some suggestions are put forward for future research. In further, it can be extended to the three-phase system to improve the power quality in various aspects. © 2020, Research Trend. All rights reserved.