It is difficult to rapid detect the failure reason of abnormal sound in valve mechanism of engine based on the existing artificial experiential auscultation method and auxiliary instrument diagnosis method. Due to this, an innovative method of using atomic absorption spectrometry (AAS) was proposed to detect abnormal sound in valve mechanism of engine in this study. Engine lubricating oil of Santana 2000 with a traveled distance of 9000-40000 Km was considered as the experimental sample. For engine lubricating oil, sampling interval was about 1000 Km and sampling batches were 48, respectively. The titanium (Ti) content in engine lubricating oil sample was determined using AAS. Then, the database of Ti content in the lubricating oil came from same model and different mileages automobile engine was established. The results demonstrated that Ti content fluctuated in a certain range with automobile different mileages. In practical engineering, determination of Ti content in lubricating oil from abnormal sound automobile engine and comparison Ti content with their content change trend chart could help the maintenance person to judge types and locations of abnormal sound in valve mechanism of engine. Using this method could reduce the automobile maintenance and reparation costs and improve the failure diagnosis accuracy of abnormal sound in valve mechanism of engine.