A multi-unit heat pump dehumidifier is presented for humidity and temperature control. Two parallel connected condensers are employed in the system, one is placed at the back of the indoor evaporator and the other is placed at outdoor environment. The fan speed and electric expansion valve opening rate are adjustable to control the air temperature out of the indoor condenser. A simulation model based on two-phase fluid network is built and validated for performance analysis in different operating condition. The system performance such as cooling/heating capacity, dehumidification rate, evaporating and condensing temperatures, energy efficiency ratio and efficiency of dehumidification are analyzed with variations of outdoor and indoor air temperature, air volumes and electronic expansion valve opening rate. The multi-unit heat pump dehumidifier is found to be capable to satisfy the cooling, heating and humidity load for all-year-round operation. And the simulation results are helpful the optimization of the system design and control.