BACKGROUND: The COVID-19 pandemic exacerbates the effects of social isolation on the mental health of middle-aged and older adults. This study aimed to explore the network structures of depressive symptoms among Chinese middle-aged and older adults before and after the COVID-19 outbreak and investigate their associations with Internet use. METHODS: Two cross-sectional datasets were obtained from the 2018 and 2020 waves of the China Health and Retirement Longitudinal Study (CHARLS). Depressive symptoms and Internet use were assessed using the Center for Epidemiological Studies-Depression Scale (CES-D) and self-reported Internet use. Network analysis was conducted to identify central symptoms and differences between the two networks and their associations with Internet use. RESULTS: Network analysis revealed that CESD3 "Felt depressed" was the central symptom of the depression network in both waves. No significant differences in network structure were observed, but significant differences in global strength and edge strength were found. Furthermore, Internet use showed a more complex association with depressive symptoms among middle-aged and older adults in wave 2. CONCLUSION: This study provides novel insights into the central features of depressive symptoms among middle-aged and older adults before and after the COVID-19 outbreak. Targeting interventions to central symptoms and strong edges may have significant implications for depression treatment. In addition, strategies aimed at enhancing Internet use guidance could potentially benefit the mental health of middle-aged and older adults.