Foreign language classroom anxiety (FLCA) is a very critical affective factor for learners' language learning and development. The present study was designed to explore the features of Chinese university students' FLCA and to investigate the possible influencing factors on the fluctuations of Chinese university students' FLCA. Two female and two male Chinese university students were selected as the participants and their in-class performances were recorded. Data collection instrument included the classroom observation, the self-rated evaluation of FLCA, and the stimulated recall interview. To capture the micro-changes of the Chinese learners' FLCA per second, an idiodynamic approach was adopted to carry out the exploratory analysis for the learners' experiences of FLCA over the language instruction. Zooming in on the microdynamic variation of the participants' FLCA, the final results indicated that Chinese university students' FLCA, both within individuals and across individuals, is characterized of a dynamic system's features. Furthermore, a series of contributing factors were identified to trigger the participants' FLCA, with the classroom activity types and the teacher's feedback being the key external factors and the gender difference and self-efficacy being the major internal factors. The idiodynamic method shed new light on exploring the FLCA from an emic and dynamic perspective and some pedagogical implications were also put forward as well.