Background Optimal fluid management in patients with COVID-19 has not been reported. This retrospective, multicenter study investigated the impact of intravenous infusion volume in the early stage of COVID-19 on clinical outcomes.Methods 127 patients from two tertiary hospitals were separated into the “conservative” and “liberal” groups based on average daily intravenous infusion volume within the first seven days after admission. Basic information, demographic and epidemiological characteristics, laboratory findings, treatments, and outcome measures were retrieved from medical records. The disease progression MESHD and prognosis were analyzed and compared.Results The average daily intravenous infusion volume within 7 days was 500 (150–700) ml/day in the conservative-strategy group (n = 87), and 1100 (1000–1288) ml/day in the liberal-strategy group (n = 40) (p < 0.001). There were no statistical differences in median age TRANS, male TRANS-to- female TRANS ratio, epidemiology, laboratory findings on admission, comorbidities, and average daily urine output within the seven days (p > 0.05). The final K+ in the liberal group was slightly higher than that at admission, and the final hematocrit level in the conservative group had a significant difference than that at admission (p < 0.05). The mean (± SD) duration of hospitalization was 22.41 ± 11.99 days in the conservative group and 25.28 ± 12.08 days in the liberal group (p = 0.120). However, compared to the liberal group, conservative group had statistically lower rates of disease progression MESHD (9.3% vs 37.5%, p < 0.001), mechanical ventilation (2.3% vs 27.5%, p < 0.001) and in-hospital mortality (2.3% vs 15.0%, p = 0.012).Conclusions Although there appeared to be no significant difference in the duration of hospitalization between using conservative and liberal fluid management strategies, the former was associated with lower rates of disease progression MESHD, mechanical ventilation and in-hospital mortality without increased nonpulmonary-organ dysfunction. These results support the importance of implementing conservative intravenous fluid infusion in the early stage of COVID-19.