The invention discloses a 
cantilever-type piezoelectric 
diaphragm pump. The 
cantilever-type piezoelectric 
diaphragm pump is composed of a vibration excitation unit, a pump cavity body and a flow channel structure. The vibration excitation unit is composed of a pump body, an adjustable pressing mechanism, a piezoelectric vibrator, a 
vibration transmission piston and a PET diaphragm. The piezoelectric vibrator is composed of a 
copper substrate and a piezoelectric 
ceramic piece. Compared with the traditional method of periphery fixing or wave joint supporting of a circular oscillator, the method of 
cantilever supporting of the rectangular piezoelectric vibrator has the advantages that deflection is large, 
tail end output amplitude is large, and simple 
harmonic frequency is low. Meanwhile, the length of a cantilever of the rectangular piezoelectric vibrator is adjustable, and therefore a vibration 
system has different vibration characteristics so as to meet different requirements for output performance. The adopted PET diaphragm material has the advantages of being good in 
abrasive resistance, dimensional stability and electrical insulation, nontoxic, impermeable, light in weight and the like, and further has the advantages of being safe and reliable, free of 
pollution and the like as a pump cavity vibrating diaphragm for conveying chemical and medical liquid. The piezoelectric vibrator is not contacted with the conveyed liquid directly, and therefore the 
piezoelectric pump can work at high working 
voltage and is good in output performance.