Coronavirus Disease-2019 (COVID-19) is an emerging acute infectious disease around the world. Therefore, it is crucial to identify the risk factors of in-hospital mortality and disease severity for COVID-19 patients. We firstly proposed a biomarker ratio, lactate dehydrogenase to albumin ratio (LAR) may be more reliable to assess the predictive value of LAR for in-hospital mortality and early identification of critical COVID-19 patients. A retrospective study was conducted including patients (≥18 years old) with laboratory-confirmed COVID-19 infection who had been discharged or had died from 1 February to 29 February, 2020. The study included 321 patients and the median age of the 321 patients was 63.0 (IQR 51.0-70.0), ranging from 19 to 95 years old and 180 (56.1%) patients were male. 142 (44.2%) patients had 1 or more coexisting comorbidity. The most common symptoms on admission were fever(289[90%]) and cough(258[80.4%]). In multivariable logistic regression, only older age (OR, 1.11; 95% CI, 1.05-1.16), WBC count (OR, 1.26; 95% CI, 1.11-1.44), lymphocyte count (OR, 0.78; 95% CI, 0.62-0.99) and LAR (OR, 1.29; 95% CI, 1.18-1.40) were found to be significantly associated with in-hospital death. ROC analysis showed that LAR had a higher AUC (0.917) and the highest specificity(84.0%) and sensitivity(84.6%). Furthermore, the results showed that LAR had a higher AUC (0.931) to differentiate critical from mild patients and had a sensitivity of 87.7% and a specificity of 82.1%. Besides, LAR had an AUC (0.861) to differentiate critical from severe patients and had a sensitivity of 86.0% and a specificity of 73.8% and the role of LAR to distinguish severe from mild patients was the worst. To the best of our knowledge, a high LAR appears to predict higher odds of mortality and differentiate critical patients from mild or severe COVID-19 patients.