Objective To explore the relationship between dropping rate and droplet coefficient, and its influence on calculation accuracy of intravenous infusion speed. Methods At the same temperature of (20±1)℃, the droplet coefficients of four common so-lvents consisting of 0.9% sodium chloride injection solution, 5% glucose injection solution, 10% glucose injection solution and glucose and sodium chloride injection solution were determined at different dropping velocities, and the drop coefficients using different solvents were compared. Results The variation trend of droplet coefficient along with the dropping rate of different solvents were similar, under the condition of low-speed infusion （0-20 drops/min）, the relationship between the dropping rate and droplet coefficient was nonlinear （taking normal saline for example, curve fitting functional formula:Y=22.75-0.27X+0.0069X2）; while in the case of medium and high speed infusion （21-120 drops/min）, the relationship was linear （taking normal saline for example, linear fitting functional formula:Y=20.31-0.022X）.Infusion speed calculation using the nominal droplet coefficient of the infusion set resulted in a calculation error of around ±10%. Conclusion The variation trend of the droplet coefficient along with the dropping rate is nonlinear, and the corresponding relationship between dropping rate and droplet coefficient obviously influences the calculation accuracy of the infusion rate.