The invention belongs to the technical field of MEMS, and especially relates to a concave electrode electrostatic actuator with a low driving voltage and a manufacturing method thereof. The electrostatic actuator comprises: an elastic film serves as an upper electrode and a plastic film serves as a concave electrode, and a sealed space is formed between a lower surface of the upper electrode and an upper surface of the concave electrode; and insulating films are arranged on the upper and lower surfaces of the electrode or the concave electrode. The manufacturing method comprises the following steps: separately performing cleaning, thermal oxidation and nitride layer vapor deposition on two SOI chips having a silicon thickness and an oxide layer thickness, and then performing exposure and etching, performing bonding, and finally filling epoxy resin and forming a concave structure through the curing shrinkage effect or vacuumizing by a vacuum suction cup. The concave electrode electrostatic actuator provided by the invention can be used as the actuator of a pump cavity or the actuator of an active valve, the micro pump processing process is not only simplified, and the driving voltage higher than 100V of the original micro pump is also reduced to tens of volts, thereby greatly improving the driving force of the electrostatic micro pump.