There are some problems in the identification of poor students in colleges and universities, such as high cost, the lack of credibility and the inconsistency of standards. Through anglicizing the consumption behavior of campus one card solution, we can depict the consumption characterization of poor students. And then we build Markov model for consumption behavior of poor students, and put forward the concept and calculation method of line index. Based on calculating the similarity index for both the consumer behavior of student model and the consumption behavior of poor student model, we can identify the poor students. This method has the characteristics of high computational efficiency, fast speed, low cost and easy data acquisition, which has consistent evaluation criteria in the same school. And the average recognition rate for poor students is than 90%. It can be used as a powerful auxiliary tool for the identification of poor students in colleges and universities.