This paper traces 9 non-English major EFL students and collects their oral productions in 4 successive oral exams in 2 years. The canonical correlation analysis approach of SPSS is adopted to study the disfluencies developmental traits under the influence of language acquisition development. We find that as language acquisition develops, the total production of disfluencies does not decrease correspondingly as we thought, but keeps constant for a period of time. While the proportions of specific disfluencies phenomena change significantly, which features the decrease of pauses and the increase self-repairs. Besides, the grammatical accuracy and language complexity have opposite effects on disfluencies traits. In the first year, disfluencies were displayed mainly as pauses and repetitions since EFL students paid more attention to grammatical accuracy; in the second year, disfluencies featured more self-repairs and less pauses because EFL students transferred their attention to language complexity. We also find language acquisition can only account for partial developmental traits of disfluencies despite of the strong correlations between them, and other factors, such as psychological or social elements, may also take effects.