Abstract: To obtain data about position, size and velocity of droplets in the electrostatic spray, a device based on in-line digital microscopic holography for spray measurement was devised and established, which has lateral measurement scope of Ø12.5mm, utmost spatial resolution of 90.5LP/mm, and the capacity of measuring the droplet in 8μm diameter. Spray measurements under the Talyor-cone mode with single metal capillary and multiple metal capillaries were carried out respectively on the established device, and the relations between average diameter, average velocity of droplets and flow rate were obtained. Results show that position, size and velocity of droplets can be obtained simultaneously during a single-shot measurement by the device, which is of great significance to the measurement on spray and the research of electrostatic spray.