The aim of this study was to explore the influence of parental intolerance of Uncertainty (IU), sensory sensitivity (SS) and Broader Autism Phenotype (BAP), as well as the severity of their children’s autism symptoms and co-morbid symptoms, on the mental health of Chinese parents of children with autism spectrum disorder (ASD). One hundred and twenty-two parents (86.9% mothers; M age = 35.64 years, SD = 4.21) of children with ASD took part. Regression and mediation analyses showed that children’s internalizing difficulties, parental BAP and IU had a direct effect, and SS had an indirect effect through IU, on parental mental health. We did not find a significant relationship between parental mental health and children’s ASD severity. Our findings emphasise the need to focus on parental traits when considering their well-being and mental health, and have implications for the design of evidence-based services to support the needs of parents.