The invention discloses a preparation method of ethylhexyl salicylate emulsion. The method comprises the following steps: (1) crushing, namely, crushing blocky solid ethylhexyl salicylate into small blocky materials through a crushing machine; (2) freezing, namely, freezing the small blocky materials crushed in step (1) into a refrigerator or a cold storage; (3) powdering, namely, grinding the materials obtained in step (2) into powder through a powdering machine; (4) milling, namely, mixing the powder obtained in step (3), a binder water solution, a dispersant and water; and milling through amilling machine to obtain the ethylhexyl salicylate emulsion. The ethylhexyl salicylate remains good and long-lasting dispersing stage, and the obtained heat-sensitive image is high in quality.