Abstract: Accurate and real-time detection of voltage and current is of great importance to unified power quality conditioner (UPQC) in realizing its comprehensive compensation performance. In order to solve the shortcomings of the traditional detection methods based on instantaneous reactive power theory, a unified detection method without phase-locked loop is proposed. The detection circuit is simplified by the removal of the phase-locked loop. The average theory is introduced to avoid the decrease of dynamic response and low filtering precision caused by the use of low pass filter. The stability of the whole system is ensured by the unified detection of voltage and current. The feasibility of the presented method are verified by theoretical analysis and simulation results.