To satisfy the increasing requirements in the collaborative development and price quotation for injection mould from the customers and companies, this paper presents a web-based cost estimation system of injection mould which can aid mould designers to evaluate the different design alternatives, implement the collaborative development of injection mould, and provide a reference for mould quotation. The overall architecture of the system based on a logical structure of four layers is established. Approach to cost estimation for injection mould is described in detail. Furthermore, a java-enabled solution together with the JESS 4.4 expert system shell and Microsoft Access 2000 is employed to develop such a networked cost estimation system. Finally, an actual example is given to demonstrate the use of the online cost estimation system of injection mould. The practical results from engineering application indicate the system can provide an effective and feasible tool to aid the evaluation of design alternatives and price quotation at the early development stages of injection mould.