ObjectiveThis study aimed to investigate burnout situation of social workers (SWs) who experienced the COVID-19 pandemic-related community lockdown 1 year before, and to assess the protective value of trait mindfulness (TM) in states of burnout.MethodWe surveyed the burnout, trait mindfulness, negative emotions (NEs) and wellbeing (WB) of 182 social workers provided services to Wuhan lockdowns community by COVID-19 one year before. Burnout were measured using the Maslach Burnout Inventory–Human Services Survey; TM using the Mindful Attention Awareness Scale; NEs using the Depression Anxiety and Stress Scale-21; and WB using the General Wellbeing Schedule. We also performed correlation regression analysis and mediation test for burnout, TM, NEs, and WB.ResultsAmong the 182 respondents, 75 (41.2%) still suffered from severe burnout. TM was negatively correlated with burnout (r = −0.623), negatively correlated with NEs (r = −0.560), and positively correlated with WB (r = 0.617). Burnout had a significantly positive correlation with NEs (r = 0.544) and a significantly negative correlation with WB (r = −0.666). Further, WB had significantly negative correlation with NEs (r = −0.758). After controlling for age, gender, marital status, educational level, and years of employment, burnout had a significantly positive predictive effect on NEs (β = 0.509), whereas TM had a significantly negative predictive effect on NEs (β = −0.334). TM played a partial mediating role in the effect of burnout on NEs, with a mediating effect and effect ratio of 0.088 and 39.7%, respectively. Burnout had a significantly negative predictive effect on WB (β = −0.598), whereas TM had a significantly positive predictive effect on WB (β = 0.299). TM played a partial mediating role in the effect of burnout on NEs, with a mediating effect and effect ratio of −0.164 and 30.3%, respectively. WB had a significantly negative predictive effect on NEs (β = −0.711), and it played a partial mediating role in the effect of burnout on NEs, with a mediating effect and effect ratio of 0.185 and 83.3%, respectively.ConclusionThe current levels of burnout among local SWs remained high 1 year after the community lockdowns. TM played a mediating role in the relationship between burnout, NEs, and WB. Concomitantly, WB played a mediating role in the relationship between burnout and NEs. Therefore, in the context of burnout, TM is a protective factor for reducing emotional stress and risks of developing psychiatric disorders through the enhancement of WB.