The maintenance of semantic consistency between numerous heterogeneous electronic product catalogues (EPC) that are distributed, autonomous, interdependent and emergent on the Internet is an unsolved issue for the existing heterogeneous EPC integration approaches. This article attempts to solve this issue by conceptually designing an interoperable EPC (IEPC) system through a proposed novel collaborative conceptualisation approach. This approach introduces collaboration into the heterogeneous EPC integration. It implies much potential for future e-marketplace research. It theoretically answers why real-world EPCs are so complex, how these complex EPCs can be explained and articulated in a product map theory for heterogeneous EPC integration, how a semantic consistency maintenance model can be created to satisfy the three heterogeneous EPC integration conditions and implemented by adopting a collaborative integration strategy on a collaborative concept exchange model, and how this collaborative integration strategy can be realised on a collaboration mechanism. This approach has been validated through a theoretical justification and its applicability has been demonstrated in two prototypical e-business applications.