It is expected that the temperature rise of solution in the liquid desiccant dehumidification process can be restrained by adding microencapsulated phase change materials (MicroPCMs) to the desiccant solution. The heat and mass transfer process of the falling film dehumidification with the microencapsulated phase change material slurry (MPCMS) were simulated. The influences of the concentration of MicroPCMs and the inlet temperature of the slurry on the dehumidification were investigated. The results show that, with the addition of MicroPCMs, the temperature rise in dehumidification process can be restrained. There is an optimum concentration of MicroPCMs to reach the peak value of interfacial mass transfer coefficient. When the concentration of MicroPCMs is 5%, the water condensation rate is 14.2% higher than that of the base fluid. It is recommended that the slurry inlet temperature be close to the onset melting temperature of MicroPCMs.