The microcapsulated phase change materials (MicroPCMs) to be used in auto internally-cooled dehumidification, with melamine?formaldehyde polymer as wall and solid liquid mixture paraffin as core, was prepared by in-situ polymerization method. In the emulsification of the core material, the non-ionic emulsifier (single or mixed) and the mixture of non-ionic emulsifier and anionic emulsifier were used, respectively. The effects of the types and contents of emulsifier on the diameter, morphology and phase change enthalpy of the MicroPCMs were studied. The results showed that, when the core is emulsified by the mixture of non-ionic emulsifier NP-10 and anionic emulsifier SDBS, the prepared MicroPCMs has low phase change enthalpy. Moreover, when the compound non-ionic emulsifier mixture of Span80 and Tween80 in proportion of 1:1, and the content of the emulsifier is 60% of the core material, the performance of the microcapsule with stirring rates of 1000 r/min in the synthesis process is the best. The mixed paraffin microcapsules have smooth and compact surfaces, and have good dispersion. The sizes of the microcapsules are uniform, and the average diameter of the microcapsules is 0.45 ?m, the phase change enthalpy is 52.48 J/g, the corresponding core content achieves 58.44%, the phase change temperature range is applicable to the auto internally-cooled liquid desiccant system with lithium chloride as desiccant.