This study examined 50 COVID-19 patients who have been cured in Anhui Province, China. The protective factors and risk factors for these patients were investigated. By comparing CT-negative and CT-positive patients, we found protective factors in blood SERO: lymphocytes, eosinophils number and %, basophils%, reticulocyte%, high fluorescence reticulocyte ratio, and reticulocyte absolute value. Comparing patients with underlying disease MESHD and without underlying disease MESHD, we found protective factors in blood SERO: lymphocytes%, basophils%, large platelets, and low-fluorescent reticulocyte ratio. Regarding the biochemistry indicators, albumin/globulin, apolipoprotein and prealbumin can be considered as protective factors for patients without lung symptoms. Urea, glucose, total bile aicd, creatinine and hypersensitivity MESHD CRP can be considered as risk factors for patients with underlying diseases MESHD. For patients with repeatedly negative and positive results in nucleic acid tests, they were at a medium level in terms of both protective and risk factors, explaining the mild symptoms and repeatedly results in nucleic acid tests.