Existing group decision-making trial and evaluation laboratory(DEMATEL) has drawbacks, such as information interaction between group experts is ignored and the inference mechanism for incomplete expert judgment information is unclear. To overcome the abovementioned drawbacks, based on the trust relationship theory in social networks and the agglomerative hierarchical clustering theory, the implementation steps for the incomplete group DEMATEL under expert interaction context are ultimately proposed by giving the inference method of missing values in the incomplete initial direct influence matrix (DIM) and the information correction method for DIM under the expert interaction context of the group DEMATEL. Finally, through the comparative analysis for a numerical example, it is reflected that the consensus degree between group experts and reliabilities of decision results are continuously improved through the experts' multiple rounds of interaction, thus the proposed method is validated to be feasible and scientific.