A droplet generating method includes the steps of providing a micro-pipe having an outlet end; providing a liquid driving device to generate a flow of a first liquid; locating and positioning the micro-pipe which extends along a vertical longitudinal axis; connecting the liquid driving device with the micro-pipe so that the first liquid flows and is emitted out from the outlet end; providing a container, which is positioned at least in-part below the micro-pipe and adapted to contain a second liquid including a liquid surface disposed at a position located between a highest and a lowest positions; and either vertically or horizontally vibrating the micro-pipe, and thereby forming a plurality of droplets of the first liquid emitted from the outlet end at a position below the liquid surface of the second liquid.