This paper studies engineering applications of rapid prototyping (RP) technology in die making of diesel engine. On demand of product development and die making of, an integrated system of reverse engineering and rapid prototyping (RE/RP) for engineering application is constructed, and effective application of RP technology in die making is thus realized. Taking the casting die for clutch house of diesel engine as an example, this paper studied the engineering application of laminated object manufacturing (LOM) technology in rapid die making and discussed related technologies as parameter setting of temperature and pressure in heat pressing, the matching of laser power and cutting speed of laser, and layout and post treatment of the prototype in RP technology. The casting die manufactured with LOM technology has satisfactory lifetime and is successfully used in 100 rough castings of clutch house for diesel engine. The manufacturing cost for the die is decreased and the production period is shortened. This paper studies engineering applications of rapid prototyping (RP) technology in die making of diesel engine. On demand of product development and die making of, an integrated system of reverse engineering and rapid prototyping (RE / RP) for engineering application is constructed, and effective application of RP technology in die making is therefore realized. Taking the casting die for clutch house of diesel engine as an example, this paper studied the engineering application of laminated object manufacturing (LOM) technology in rapid die making and discussed related technologies as parameter setting of temperature and pressure in heat pressing, the matching of laser power and cutting speed of laser, and layout and post treatment of the prototype in RP technology. The casting die manufactured with LOM technology has satisfactory lifetime and is successfully used in 100 rough castings of clutch house for diesel engine. The manufacturing cost for the die is decreased and the production perio d is shortened.