Nowadays， it is of great importance to build proper load models with practical parameters. However， due to the large numbers of equipment involved， increasing complexity in element structures， time varying characteristics and dispersibilities of load structures and parameters， it is essentially difficult to achieve this. This paper gives an overview on the research and development of power system modeling， and presents a descriptive review of several essential challenges in load modeling. A load area integral equivalence and parameter identification scheme is proposed. This scheme is based on an online dominant parameter identification method. Finally， key techniques for implementing the scheme are summarized with preliminary solutions， including load area partitioning， disposal of electrically related load groups， disposal of larger generation access points and key load groups.