Abstract: Background On March 11, 2020, the World Health Organization declared its assessment of COVID-19 as a global pandemic. Effective therapeutic drugs are urgently needed to improve the overall prognosis of patients, but currently no such drugs are available. Methods Patients in the study were divided into a heparin and a control group based on whether low molecular weight heparin (LMWH) was used. D-dimer, C-reactive protein (CRP), peripheral blood lymphocyte percentage, interleukin-6, and other indices in 42 patients with novel coronavirus pneumonia were retrospectively analyzed to compare and evaluate the progress of patients before and after LMWH treatment. Results Compared to the control group, D-dimer levels in the heparin group significantly increased before treatment, and there was no significant difference after treatment. There was no significant difference in the change of CRP levels between the two groups of patients before and after LMWH treatment, and levels for both groups were significantly lower after, compared to before, treatment. Compared to the control group, patients in the heparin group had a higher percentage of lymphocytes after treatment and lower levels of interleukin-6; these differences were statistically significant. Conclusions Under conventional antiviral treatment regimens, LMWH can improve hypercoagulability, inhibit IL-6 release, and counteract IL-6 biological activity in patients. LMWH has potential antiviral effects and can help delay or block inflammatory cytokine storms. It can also increase the lymphocytes (LYM%)of patients and has the potential for treatment of COVID-19.