In our study, the elevation of serum SP-D levels was positively associated with longer hospitalization duration, an indicator of slow recovery, and higher CT imaging scores, suggesting that the serum SP-D level may serve as a biomarker of disease severity for stratifying the COVID-19 patients at an early stage, the results of ROC analysis and multivariate logistic regression analysis also confirmed this. Here, SFTPD is linked to COVID-19.