The invention provides an emulsified petroleum wax which is prepared by the following steps: adding petroleum wax, a surfactant and a Tween assistant into a reactor, melting by heating, uniformly mixing at low speed, heating to the emulsification temperature, putting a water-soluble surfactant into a beaker, adding distilled water, and heating to the emulsification temperature for dissolution, thereby obtaining a surfactant water solution, and while stirring at high speed, slowly adding the surfactant water solution into the reactor, stirring for 15-30 minutes, adding the balance of deionized water heated to the emulsification temperature in batches, and stirring for phase inversion to form an oil-in-water emulsion; and defoaming by ultrasonic vibration, and cooling to room temperature to obtain the emulsified wax. The emulsified petroleum wax has both hydrophilicity and hydrophobicity, effectively lowers the cohesive force among the petroleum wax molecules, further lowers the surface tension of the emulsion, and can adsorb more surfactant molecules on the interface to form tiny emulsion particles, thereby enhancing the stability of the emulsified petroleum wax.