A group of powders (40) for making a wick structure of a heat pipe includes main powders (50) and supplemental powders (60). The melting point of the supplemental powder is lower than that of the main powder. During a sintering process, the powders are filled in a casing of the heat pipe and have a eutectic reaction between the main powders and the supplemental powders to form the wick structure. The temperature for the eutectic reaction is lower than the melting temperature of the supplemental powders.