A multi-heat pump provides the benefits of comfort, energy conservation and easy maintenance. Recently, the multi-heat pump has been widely employed in small and medium-sized buildings. However, the control algorithm of the multi-heat pump are limited in the open literature due to complicated operating conditions. In this study, the MIMO control algorithm using integral optimum regulator was designed and the control performance of it was analyzed. In addition, system model of the control plant was developed by PRBS system identification scheme. The MIMO controller adopting the integral optimum regulator yielded satisfactory control performance results.