A custom quartz tuning fork which is 5 times larger than commercial standard quartz tuning fork and operated at the 1st overtone resonance mode was used and optimized to improve the sensitivity of the quartz-enhanced photoacoustic spectroscopy spectrophone. The optimum ecxiting position for the laser beam was researched. Two resonance antinodes were found in the 1st overtone resonance, and the maxium signal amplitude was obtained at a distance of 8 mm from the tuning fork support. Acoustic micro-resonantors with three different inner diameters were configured with the custom tuning fork to evaluate the performance of the quartz-enhanced photoacoustic spectroscopy spectrophone. With an optinal parameters, a sensitivity gain factor of 30 was achieved with respect to the signal amplitude obtained by the bare tuning fork without acoustic micro-resonantors.