The invention discloses a direct-current droplet generator and a preparation method thereof. The generator is characterized in that the generator has a structure in which all electrodes are placed above a 
solid surface and do not need to be grounded, so that the direct-current 
liquid drop generator can be constructed on any surface including a block body, a thin film and a 
coating; the droplet generator structure comprises a 
solid hydrophobic surface, an upper 
electrode, a collector pin, a lower 
electrode, an upper 
electrode lead and a lower electrode lead. The 
solid surface is a hydrophobic surface made of any artificial or natural materials, the upper electrode and the lower electrode are placed on the 
solid surface at a certain interval, the current collecting needle can be of an independent conductive tip structure and can also be directly machined on the electrode, and the generator can collect 
electric energy by impacting the surface through liquid drops. Compared with the prior art, the direct-current droplet generator can be constructed on any 
solid surface, the collected liquid 
mechanical energy is converted into the 
electric energy with the direct-current characteristic, and the direct-current droplet generator has the advantages of being simple in preparation process and low in cost. The open-circuit 
voltage of the direct-current 
liquid drop generator is up to kilovolt, a 
power management circuit is not needed, and the direct-current 
liquid drop generator can directly drive micro electronic devices to work or charge an 
energy storage unit. The structure of the direct-
current generator has the functions of power generation, rectification and 
energy storage at the same time, a new technology based on solid-
liquid interface water energy collection is developed, and the practical progress of 
water energy collection is greatly accelerated; meanwhile, the device is also a sensor or a probe. Due to the fact that the device achieves effective separation of charges, the device has extremely high application value in the aspects of droplet energy collection and self-driven sensing.