This paper conducts a theoretical review on volunteer motivation and finds that: (1) The currently prevalent conceptual model of volunteer motivation, the functional model, seems to overlook purely altruistic motivation; (2) Due to the great differences in measurement tools for volunteer motivation, it is difficult to compare and generalize the influencing factors of volunteer motivation; (3) Regarding the influencing effects of volunteer motivation, relevant research in the practical field is urgently needed but limited in quantity. Based on the above findings, specific suggestions are put forward for future research on volunteer motivation.