A pump system comprising a piezoelectric pump, a piezoelectric actuator and a driving system for driving the piezoelectric actuator of the piezoelectric pump, the piezoelectric actuator having a first terminal and a second terminal, characterized in that the driving system comprises: a voltage conversion module converting a first DC voltage into a second DC voltage; a frequency control module electrically connected with the voltage conversion module and the piezoelectric actuator, wherein the frequency control module searches a resonant working frequency of the piezoelectric actuator through circuit oscillation and generates a switching signal according to the resonant working frequency; a voltage switching module electrically connected with the frequency control module, converting the second DC voltage into an AC voltage according to the switching signal so as to drive the piezoelectric actuator; a voltage dividing module electrically connected with the voltage conversion module; and a detecting module comprising a gas pressure sensor and a microcontroller, wherein the gas pressure sensor is configured to detect a gas pressure of the piezoelectric pump and accordingly outputs plural detected gas pressure values, wherein the microcontroller is electrically connected with the gas pressure sensor and the voltage dividing module to implement actions comprising: acquiring an actual gas pressure change amount of the piezoelectric pump within a specified time interval by calculating the detected gas pressure values; issuing an adjusting signal to the voltage conversion module according to a result of comparing the actual gas pressure change amount with a predetermined gas pressure change amount; wherein the voltage conversion module adjusts the second DC voltage according to the adjusting signal, so that the gas pressure of the piezoelectric pump is correspondingly adjusted to make the actual gas pressure change amount approaching to the predetermined gas pressure change amount. a voltage conversion module converting a first DC voltage into a second DC voltage; a frequency control module electrically connected with the voltage conversion module and the piezoelectric actuator, wherein the frequency control module searches a resonant working frequency of the piezoelectric actuator through circuit oscillation and generates a switching signal according to the resonant working frequency; a voltage switching module electrically connected with the frequency control module, converting the second DC voltage into an AC voltage according to the switching signal so as to drive the piezoelectric actuator; a voltage dividing module electrically connected with the voltage conversion module; and a detecting module comprising a gas pressure sensor and a microcontroller, wherein the gas pressure sensor is configured to detect a gas pressure of the piezoelectric pump and accordingly outputs plural detected gas pressure values, wherein the microcontroller is electrically connected with the gas pressure sensor and the voltage dividing module to implement actions comprising: acquiring an actual gas pressure change amount of the piezoelectric pump within a specified time interval by calculating the detected gas pressure values; issuing an adjusting signal to the voltage conversion module according to a result of comparing the actual gas pressure change amount with a predetermined gas pressure change amount; wherein the voltage conversion module adjusts the second DC voltage according to the adjusting signal, so that the gas pressure of the piezoelectric pump is correspondingly adjusted to make the actual gas pressure change amount approaching to the predetermined gas pressure change amount.