The emulsified paraffin wax was prepared on the basis of the hydrophilic lipophilic balance （HLB） theory. By adjusting the emulsification process， the emulsified paraffin wax demolding agent for concrete with good storage stability was obtained. The mortar demolding test was carried out to determine the amount of mortar adhesion on the mold surface after demolding， the number and size of pores on the surface of the mortar test block， and the surface hardness of the mortar test block， as compared with machine oil as the demolding agent. The results show that the emulsified paraffin wax demolding agent can effectively reduce the number and size of pores on the surface of the mortar test block. The reduction of amount of mortar adhesion on the mold surface and the improvement of the surface hardness of the mortar test block are not satisfactory， though it can be improved by increasing the application times of the emulsion paraffin wax demolding agent.