In recent years, the prevention of telecom fraud has been an important theme of security education in colleges and universities in China, but the cases of telecom fraud are still common. In depth interviews were conducted on 10 typical cases of telecom fraud in L University. Based on the grounded theory research, it is found that the current situations of reducing risk perception of telecom fraud among college students can be divided into four categories, namely, self efficacy type, stress response type, pushing the envelope type, and halo effect type. The existing safety education is misplaced and lacks effectiveness, while the safety culture, experience transfer and consumption concept in the informal institutions can effectively match the above four types of risk perception situations, so as to improve the pertinence of safety education for college students.