In order to prevent college students from tragic events, which mostly result from falling into illegal net loan, a net loan risk monitoring platform of college students was established based on the microblog visualization. Based on the calculation model of risk degree (CMRD) and the calculation model of relational closeness (CMRC), a visual system, a user relationship analysis system and an early warning system were constructed on the platform. Through the CMRD, the risk degree of micro-blog net loan contents can be worked out to decide whether warning behaviors are necessary. Through the CMRC, the closeness of net loan bloggers with users can be obtained a propagation map. The key nodes can be cut off by internet security officers in time, which can prevent further propagation of the contents of the microblog net loan. The platform can effectively alleviate the tense situation of college students and illegal online loans.