Objective To investigate the levels of caregiver burden and illness cognition of parents of autistic children, and to analyze the impact of illness cognition on caregiver burden. Methods Using convenience sampling method, 215 parents of autistic children in three autistic children rehabilitation institutions in Wenzhou were investigated. The instruments included a demographic data questionnaire, the Zarit Caregiver Burden Interview, and the Illness Cognition Questionnaire. Hierarchical regression was performed to examine the moderation effect. Results The participants scored 40.00±16.85 on caregiver burden, 15.11±4.39 on helplessness in illness cognition, 15.60±3.75 on acceptance, and 16.77±4.00 on perceived benefits, respectively. After controlling demographic variables, parents′ helplessness positively predicted whereas perceived benefits negatively predicted, caregiver burden （both P<0.05). Perceived benefits moderated the impact of helplessness on caregiver burden (R2=0.012, P<0.05). Conclusion Parents of autistic children experience high level of caregiver burden, and their perceived benefits buffer the impact of helplessness on caregiver burden. Medical staff need to promote positive cognition of parents of autistic children to alleviate the impact of negative cognition on caregiver burden.