Background Asthma is a chronic disease that seriously harms the health of patients. Oxidative stress is involved in asthma. As an oxidative stress-inducible protein, sestrin2 is elevated in oxidative stress-related diseases. We aimed to explore whether sestrin2 was involved in asthma. Methods Seventy-six subjects (44 in the asthma group, 32 in the control group) were recruited in this study. Plasma sestrin2 levels, peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV1) % predicted, forced vital capacity (FVC) % predicted and FEV1/FVC ratio were measured in controls and in asthmatics both during an exacerbation and when controlled after the exacerbation. Results The asthma group had a significant higher sestrin2 level than the control group (asthmatics during exacerbation, 1.75 +/- 0.53 ng/mL vs. 1.32 +/- 0.48 ng/mL, p < 0.001; asthmatics when controlled after the exacerbation, 1.56 +/- 0.46 ng/mL vs. 1.32 +/- 0.48 ng/mL, p = 0.021, respectively). In addition, sestrin2 was negatively correlated with FEV1% predicted and FEV1/FVC ratio in asthmatics during exacerbation (r = - 0.393, p = 0.008; r = - 0.379, p = 0.011; respectively). Moreover, negative correlations between sestrin2 and FEV1% predicted and FEV1/FVC ratio also existed in asthmatics when controlled after the exacerbation (r = - 0.543, p < 0.001; r = - 0.433, p = 0.003 respectively). More importantly, multiple linear regression analysis demonstrated that FEV1% predicted was independently associated with sestrin2 in asthmatics both during exacerbation and when controlled after the exacerbation. Conclusions Sestrin2 is involved in asthma. Sestrin2 levels increase in asthmatics both during exacerbation and when controlled after the exacerbation. In addition, sestrin2 is independently associated with FEV1% predicted.