Piezoelectric cantilever has been extensively used in MEMS/NEMS for its superior performance. In order to reduce noise in piezoelectric cantilever signal acquisition, a comprehensive theoretical and numerical analysis of a cold discharge charge sensitive amplifier is conducted in the paper. A cold discharge charge sensitive amplifier with charge voltage sensitivity of 23.4 mV/pC is designed and utilized in piezoelectric cantilever displacement sensing system with resolution on the order of nanometer. Experimental results indicate that cold discharge charge sensitive amplifier does exhibit superior noise performance than classic charge sensitive amplifier, which matches well with theoretical expectation and simulation result. Cold discharge charge sensitive amplifier is a new choice for low noise piezoelectric signal acquisition.