Abstract: Investigats the parameter estimation of shared plants by the server under Internet based shared control system,which is a time-varying and time-delay system. System online identification conditions and difficulties were analyzed. Control technology, network communi-cation technology and system online identification technology are introduced. It shows that the server can identify the model parameters of the shared plants in the Internet based shared control system. To use the identification result without influence of network factor as the reference, it is basically matched that the two identifications result. The proposed online identification method is proved feasible. It can identify the shared plants as separated from the server spatially. Simultaneously the areas of application of the system online identification are seen to be expanded.