Firstly, from the perspective of multiplex network theory, a multi-channel diffusion model of the biased perceived iatrogenic risk (BPIR) in the context of the Internet of Healthcare Systems (IHS) is constructed in this paper. The model considers the interactive effects of perceived diffusion of BPIR among various information channels under IHS. Secondly, the threshold to distinguish whether BPIR spreads among the public under the IHS is obtained. Finally, the parameters of the established theoretical model are estimated and the case analysis is conducted using actual data. The results indicate that: 1) Compared with mere the publicity of correct cognition, the diffusion efficiency of BPIR under IHS would be significantly reduced when the correct cognition dissemination is combined with cognitive correction; 2) Compared with the in-depth control of the diffusion of BPIR in only one or two channels, moderate intervention across all channels results in a more significant reduction in the diffusion efficiency of BPIR.