Objective To explore the early predictors of the development of the novel coronavirus infection （COVID-19） into severe and critical forms. Methods COVID-19 patients hospitalized in the Department of Intensive Care Medicine， Infection ward， Respiratory and Critical Care Medicine of the First Affiliated Hospital of Guangxi Medical University from December 2022 to March 2023 were selected as the study objects， and were divided into mild/medium group， severe group， and critical group according to the severity of illness during hospitalization. General clinical data and early laboratory results of the three groups were collected and compared. Results A total of 242 patients with novel coronavirus infection were included， including 117 mild/medium patients， 55 severe patients， and 70 critically severe patients. There were 165 males and 77 females with a median age of 70 （59，80） years. The age， sex， diabetes， heart disease， stroke， combined pneumonia， combined bloodstream infection， APACHE Ⅱ score， respiratory rate on admission， systolic blood pressure， and early white blood cell count （WBC）， lymphocyte count （LYM）， urea， creatinine， albumin， C-reactive protein， D-dimer， interleukin-6 （IL-6）， and calcium reduction of patients in the three groups had significant （all P < 0.05）. Ordered logistic regression shows， previous heart disease， stroke， combined bloodstream infection， WBC， high IL-6 level， and low LYM level were independent risk factors for severe and critical COVID-19 infection ［odds ratio （OR） and 95% confidence interval （95%CI） were 3.253（1.694 ~ 6.246）， 5.251（2.378 ~ 11.592）， respectively. 6.920（2.499 ~ 19.189）， 1.111（1.041 ~ 1.186）， 1.003（1.001 ~ 1.006）， 0.571（0.353 ~ 0.926）］. ROC curve analysis showed that WBC， LYM， IL-6 and their combined detection had certain predictive value for the severity of COVID-19 （all P < 0.05）， and the combined detection of WBC， LYM and IL-6 had better predictive value than a single indicator （P < 0.05）. Conclusion Previous heart disease， cerebrovascular disease， early combination of bloodstream infection， high levels of IL-6， white blood cell count， and low lymphocyte levels at admission were independent risk factors that helped to predict the severity of COVID-19 infection early. The combined detection of WBC， LYM and IL-6 has certain predictive value for the development of severe and critical COVID-19.