In order to improve the power quality of threephase fourswitch (TPFS) converter in unbalanced grid, a finite control sets model predictive power control scheme was proposed. The operation principle and voltage vectors were analyzed and the power predictive model was established. A reference power calculation method using the grid voltages and their quadrature signals was designed. The optimal voltage vector could be selected based on the cost function. It was unnecessary to use phase lock loop to extract sequence components, and easy to be implemented. The simulation and experimental results showed that, under unbalanced grid voltages, the proposed method could reduce the gridconnected current harmonic distortion, eliminate power fluctuation and improve the power quality of the TPFS converter.