This present disclosure provides a risk assessment method and system for affordable housing application in a smart city based on Internet of Things. The risk assessment method is executed by the management platform, and the risk assessment method includes obtaining a query request for a risk of the affordable housing application from the service platform, wherein the query request is generated by the user platform based on an input of the affordable housing application by an applicant through the user platform; in response to the query request, through a management sub-platform corresponding to the management platform and a service sub-platform corresponding to the service platform, obtaining relevant information of the applicant and his/her related persons thereof, and determining the risk of the affordable housing application of the applicant; and sending the risk of the affordable housing application to the service platform.