A heat pipe (50) and a method (100) of producing the heat pipe are disclosed. The method includes the following steps: (1) inserting a mandrel (10) into a hollow metal casing (20) with a porous structure (30) combined to an outer surface of the mandrel; (2) filling powders (40) into a space formed between the hollow metal casing and the porous structure; (3) sintering the filled powders; (4) drawing the mandrel out of the hollow metal casing; and (5) sealing the hollow metal casing with a working fluid filled therein. The heat pipe produced by this method includes a composite wick structure (60) arranged in the hollow metal casing. By using this method, the mandrel can be easily drawn out of the hollow metal casing after the filled powders are sintered.