Background: Glucocorticoids are widely used in the treatment of various pulmonary inflammatory diseases, but they are also often accompanied by significant adverse reactions. Published guidelines point out that low dose and short duration systemic glucocorticoid therapy may be considered for patients with rapidly progressing COVID-19 while the evidence is still limited. Methods: We comprehensively searched electronic databases and supplemented the screening by conducting a manual search. We included RCTs and cohort studies evaluating the effectiveness and safety of glucocorticoids in children and adults with COVID-19, SARS and MERS, and conducted meta-analyses of the main indicators that were identified in the studies. Results: Our search retrieved 23 studies, including one RCT and 22 cohort studies, with a total of 13,815 patients. In adults with COVID-19, the use of systemic glucocorticoid did not reduce mortality (RR=2.00, 95% CI: 0.69 to 5.75, I 2=90.9%) or the duration of lung inflammation (WMD=-1 days, 95% CI: -2.91 to 0.91), while a significant reduction was found in the duration of fever (WMD=-3.23 days, 95% CI: -3.56 to -2.90). In patients with SARS, glucocorticoids also did not reduce the mortality (RR=1.52, 95% CI: 0.89 to 2.60, I2=84.6%), duration of fever (WMD=0.82 days, 95% CI: -2.88 to 4.52, I2=97.9%) or duration of lung inflammation absorption (WMD=0.95 days, 95% CI: -7.57 to 9.48, I2=94.6%). The use of systemic glucocorticoid therapy prolonged the duration of hospital stay in all patients (COVID-19, SARS and MERS). Conclusions: Glucocorticoid therapy was found to reduce the duration of fever, but not mortality, duration of hospitalization or lung inflammation absorption. Long-term use of high-dose glucocorticoids increased the risk of adverse reactions such as coinfections, so routine use of systemic glucocorticoids for patients with COVID-19 cannot be recommend.