Acetone detection is crucial for diagnosing diseases such as diabetes and lung cancer. Therefore, it is essential to design a room-temperature acetone gas sensor with fast response and recovery times, high sensitivity, high selectivity, and a low detection limit. However, current acetone gas sensors face challenges in achieving high-selectivity detection at room temperature. This study primarily utilizes self-assembled organic monolayer functionalized MIL-88B to prepare selectivity acetone sensors. The results show that the detection sensitivity of the improved sensor to acetone is significantly improved. Compared with the MIL-88B sensor (0.1 ppm), the response value of the MIL-88B@3-aminopropyltrimethoxysilane (APTMS) sensor is increased by about 61.9%. The response to 10 ppm acetone is 83, and the selectivity is greatly improved at room temperature. This can be attributed to the chemical interactions between acetone molecules and APTMS on the sensor surface, which improves the sensor's specific recognition ability for acetone. Additionally, the sensor exhibits better stability and shorter response and recovery times. Consequently, the APTMS functionalization of MIL-88B presents an effective method for preparing room-temperature acetone sensors, combining high sensitivity and selectivity, and offering potential for non-invasive disease diagnosis.