A piezoelectric pump comprising: a piezoelectric actuator; a driving system for driving the piezoelectric actuator; a voltage conversion module converting a first DC voltage generated by a power source into a second DC voltage; a switching module electrically connected with the voltage conversion module and the piezoelectric actuator, converting the second DC voltage into an AC voltage so as to drive the piezoelectric actuator; a detecting module comprising a feedback circuit and a gas pressure sensor, wherein the feedback circuit is electrically connected with the switching module, and the gas pressure sensor is configured to detect a gas pressure of the piezoelectric pump and accordingly generates a detected gas pressure value; a voltage dividing module electrically connected with the voltage conversion module; and a microcontroller electrically connected with the voltage dividing module, the switching module, the feedback circuit and the gas pressure sensor, wherein the microcontroller issues a driving signal to operate the switching module at a range of frequencies; the microcontroller acquires at least one electric power reference value through the feedback circuit, wherein the electric power reference value corresponds to the operation of the switching module at the range of frequencies; the microcontroller acquires a working frequency of the AC voltage according to the electric power reference value and operating the piezoelectric actuator at the working frequency; the microcontroller acquires an actual gas pressure change amount of the piezoelectric pump within a specified time interval by calculating the detected gas pressure values; and the microcontroller issues an adjusting signal to the voltage conversion module through the voltage dividing 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 piezoelectric actuator; a driving system for driving the piezoelectric actuator; a voltage conversion module converting a first DC voltage generated by a power source into a second DC voltage; a switching module electrically connected with the voltage conversion module and the piezoelectric actuator, converting the second DC voltage into an AC voltage so as to drive the piezoelectric actuator; a detecting module comprising a feedback circuit and a gas pressure sensor, wherein the feedback circuit is electrically connected with the switching module, and the gas pressure sensor is configured to detect a gas pressure of the piezoelectric pump and accordingly generates a detected gas pressure value; a voltage dividing module electrically connected with the voltage conversion module; and a microcontroller electrically connected with the voltage dividing module, the switching module, the feedback circuit and the gas pressure sensor, wherein the microcontroller issues a driving signal to operate the switching module at a range of frequencies; the microcontroller acquires at least one electric power reference value through the feedback circuit, wherein the electric power reference value corresponds to the operation of the switching module at the range of frequencies; the microcontroller acquires a working frequency of the AC voltage according to the electric power reference value and operating the piezoelectric actuator at the working frequency; the microcontroller acquires an actual gas pressure change amount of the piezoelectric pump within a specified time interval by calculating the detected gas pressure values; and the microcontroller issues an adjusting signal to the voltage conversion module through the voltage dividing 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.