In this study, mold core of can type lens for optical communication has been fabricated and heat transfer analysis has been conducted. Through this study, results were obtained as follows. Surface roughness of upper and lower cores by ultra precision grinding were Ra 0.002074(um) and 0.004316(um), respectively. Design P-V and Bestfit P-V as shape accuracy of upper core were 0.0858(um) and 0.0843(um), respectively, and those of lower core were 0.0957(um) and 0.0546(um), respectively. The temperatures of upper and lower surfaces of lens during machining obtained by heat transfer analysis were 576.05℃ and 576.4℃, respectively. In case of inner sleeve, it was estimated that the temperature of the side surface were 575.95℃ by heat transferred from lower core. The maximum and minimum temperatures of lower surface of lens were 576.4℃ and 575.96℃, respectively, according to the positions of holes for air circulation from out side.