Herein, this study describes a sample preconcentration apparatus based on a metal–organic framework (MOF) of NH₂-UIO-66@PDMS adsorbent, which is first coupled to photoacoustic spectroscopy (PAS) technology for detection of acetone. The MOF selectively traps acetone out of complex samples and releases it into the photoacoustic (PA) cell, where PA signal intensity is recorded by PAS sensing system based on a cheap amplitude modulated UV LED as light source. The signal intensity is enhanced by 11 times after preconcentration of NH₂-UIO-66@PDMS (100 mg). The preconcentration apparatus not only enhances sensitivity of sensor, but also promotes the anti-interference ability for common interferents (carbon dioxide, oxygen and water vapor, ethanol, propanol, etc.) of the sensor. As expected, the established PA sensor possesses a detection limit of 0.23 ppm for measuring acetone, which can feasibly be applied for the analysis of acetone in patients breath samples. This work provides a good example of the preconcentration effect of MOF for promoting PA sensor analytical performance, and the prospect of medical diagnosis.