The invention provides a method for measuring diameter and volume of droplets based on a coplanar capacitor. The method comprises the following steps: decomposing total capacitance of the coplanar capacitor during deposition of droplets so as to obtain the sum of incremental capacitance of the deposited droplets to the coplanar capacitor and intrinsic capacitance of the coplanar capacitor during absence of deposition of droplets; calculating the total incremental capacitance of the deposited droplets to the coplanar capacitor; establishing a relation of the incremental capacitance of the wholedroplets to the coplanar capacitor according to the total incremental capacitance produced by the droplets, and calculating an inverse function to obtain a mathematic relation between the incrementalcapacitance and the deposited droplets and the radius of a circle contacted with the coplanar capacitor; and performing inversion calculation to obtain the volume and diameter of the droplets by virtue of the obtained mathematic relation. According to the method for measuring the diameter and volume of the droplets based on the coplanar capacitor provided by the invention, starting from the surface tension characteristic of droplet deposition, the surface tension characteristic problem of the droplets deposited on the object surface is fully considered, and the measuring accuracy is greatly improved.