Online financial service is an essential part of consumption services provided by companies in modern society. It is vital to figure out the underlying mechanisms that influence online financial service use of college students in China, which is seldom explored. Drawing on the theory of planned behavior (TPB), this study explores the effect of personality traits (i.e., materialism) and its joint effect with attitude on online financial service use of college students. Moreover, we examined the interaction effects of key variables in TPB in the context of online financial services. The results indicated that the materialism value of Chinese college students has no direct effect on their intention to use online financial services but exerts an indirect effect through their attitude toward online financial services. College students' attitudes and perceived behavioral control are associated with their subjective norms, and in turn, affect their use intention of online financial services. In addition, perceived risk and perceived usefulness of online financial services also affect use intention through attitude and perceived behavioral control. The discussion of key findings, implications, and conclusions are provided.