Using the method of analogy, this paper built the social information field, information field force model and the information diffusion dynamics model to study the dynamic mechanism and the law of the movement regarding how misconduct information moves among nodes in the web forum. It also constructed the web forum misconduct information diffusion complex network simulation model to study the diffusion intensity of misconduct information and its influencing factors. The conclusion is that, under the force of the field, the information flows from the high potential node to the low potential node, during which resistance is generated inside and outside the diffusion channel. In the complex network of the web forum, the diffusion intensity of misconduct information displays an increasing trend as the possibility of reconnection among broken nodes becomes higher. The main factor that determines the diffusion intensity of the misconduct information is the average shortest path. It also increases when the interaction frequency turns higher. Using the method of analogy, this paper built the social information field, information field force model and the information of dynamics movement and the law of the movement regarding how misconduct information moves among nodes in the web forum. It also constructed the web forum misconduct information diffusion complex network simulation model to study the diffusion intensity of misconduct information and its influencing factors. The conclusion is that, under the force of the field, the information flows from the high potential node to the low potential node, during which resistance is generated inside and outside the diffusion channel. In the complex network of the web forum, the diffusion intensity of misconduct information displays an increasing trend as the possibility of reconnection among broken nodes becomes higher. The main factor that determines the diffusion intensity of the misconduct information is the average shortest path. It also incr eases when the interaction frequency turns higher.