Although little is known about the current situation regarding autism spectrum disorder (ASD) in mainland China, psychiatric disorders are common among Chinese mothers of preschool children with ASD. Previous studies showed ASD child's behavioral symptoms, maternal anxiety, and maternal depressive symptoms were associated with overall parenting stress in northern China. In the present study, we retrospectively analyzed medical records at the hospital related to neuropsychiatric symptoms, parenting stress and social support in mothers of children with ASD from southern China. A total of 80 mothers of children with ASD were screened. Among them, 34 mothers were in low-functioning ASD group (L-ASD group) and 46 mothers were in high-functioning ASD group (H-ASD group). Identification of the ASD cases was confirmed with a Revised Autism Diagnostic Inventory. Neuropsychiatric symptoms, parenting stress and social support were measured by neuropsychiatric inventory (NPI), parenting stress index short form (PSI-SF), and multi-dimensional scale of perceived social support (MSPSS). Total mean score of the NPI in the L-ASD group was significantly higher than that in the H-ASD group (P<0.01). The subscale scores of NPI, including depression, anxiety, apathy, irritability, agitation, night time behavior disturbances and change in appetite were significantly higher in the L-ASD group than those in the H-ASD group (P<0.01 or P<0.05). Meanwhile, the total PSI-SF scores and the scores of parental distress (PD), parental-child dysfunctional interaction (PCDI) and difficult child (DC) in the L-ASD group were significantly higher than those in the H-ASD group (P<0.01 or P<0.05). The total score of MSPSS was also higher in the L-ASD group than in the H-ASD group (P<0.01). This study goes further to show the neuropsychiatric symptoms and parenting stress are significantly higher in mothers of children with ASD, and more social supports are needed for mothers of children with ASD from southern China, especially for mothers of children with low-functioning ASD.