For the key problem of droplet analyzer optical fiber and capacitance sensor poor measurement repeatability which impact droplet analysis measurement accuracy, the sensor structure was redesigned by increasing shielding structure in the external of capacitance sensor annular plate.Digital capacitance signal measurement method was used instead of excitation type analog measurement method.The minimum and maximum standard deviations measured by capacitance sensor are 0.001 7 pF and 0.002 4 pF.The optical fiber signal measurement circuit was improved, and infinite gain low-pass filter was used which avoided self-excited oscillation caused by high magnification.The peak standard deviation measured by optical fiber sensor is 0.019 9 V, and the droplet analyzer accuracy is improved.