Digital microfluidics based on electrowetting-on-dielectric is an emerging popular technology that manipulates single droplets at the microliter or even the nanoliter level. It has the unique advantages of rapid response, low reagent consumption and high integration. Electrowetting-on-dielectric device based digital microfluidics has shown enormous advantages in biology, medicine and chemistry and so on, and it has been used extensively in these subjects for driving single droplet. However, the lack of feedback on droplet position will result in a phenomenon that the droplet cannot be successfully driven. In that case, the droplet fails to complete the programming path. The principle of droplet position estimator based on the equivalent capacitance was adopted, and the equivalent capacitance of two adjacent driving electrodes and droplet was used as the feedback control object. The electrode capacitance was used, which was an inherent electrical property of electrowetting-on-dielectric digital microfluidics devices, to determine the position of any droplet composition in the interval of two electrodes. Capacitance was an electrical property which was sensitive to the presence of a droplet and independent of actuation signal frequency. The dimensionless nature of this droplet position estimator was independent of the droplet compositions, and its applicability was more extensive. Finally, the experimental results showed that the droplet position estimator based on the equivalent capacitance can greatly improve the success rate of the continuous motion. Thus the droplet can be driven to the established destination according to the programming path. A capacitance-based position estimator was implemented which can continuously track the displacement of a droplet within the interval of two adjacent electrodes. The displacement of a droplet was estimated through a dimensionless ratio of two electrode capacitances.