As part o f a longitudinal study, this paper reports an SEM analysis of the relationship between types of English learning motivation and learners' self-identity changes. The data were collected through a questionnaire, implemented 5 times in four years, on over 1300 students from five universities in Beijing. SEM results of the 5 tests show that types of English learning motivation and self-identities influenced each other, with the former having greater effect on the latter. As time went by, the effect of English learning motivation on self-identities decreased, while that o f self-identities first descended and then ascended. Positive correlations were constantly found between immediate achievement motivation and learning situation motivation, and between going abroad motivation and subtractive identity change.