Previous research and theory suggest that chronic low back pain is closely related to sleep, anxiety, and mindfulness levels. This study investigated the relationship between cognitive and somatic pre-sleep arousal and pain-related anxiety in women with chronic low back pain and the moderation effect of mindfulness on this relationship. We collected quantitative data from 181 female patients with chronic back pain who visited university hospitals and used self-reporting questions to measure pain-related anxiety, cognitive and somatic pre-sleeping arousal, sleep quality, and mindfulness. SPSS 23.0 and AMOS 22.0 were used to analyze the data. We employed a structural equation model to examine the relationship between pain-related anxiety, cognitive and somatic pre-sleep arousal, and sleep quality. Then, we used a PROCESS macro no. 7 to examine the moderation effect of mindfulness on the relationship between these variables. Cognitive and somatic pre-sleep arousal completely mediated pain-related anxiety and sleep quality (p < .01), and the direct effect of pain-related anxiety on sleep quality was non-significant. Mindfulness had a moderation effect on the relationship between pain-related anxiety and cognitive pre-sleep arousal (p < .05). However, there was no significant moderation effect of mindfulness on the relationship between pain-related anxiety and somatic pre-sleep arousal and pain-related anxiety and sleep quality. Mindfulness plays an important role in women with chronic low back pain, especially related to sleep quality and pain-related anxiety. Study limitations and suggestions for future research are also presented.