The invention provides a vehicle-mounted lithology and unfavorable geological precursor characteristic identification system and a method thereof. The vehicle is used for carrying a navigation positioning module, a rock element testing module, a rock sampling module, an automatic rock sample grinding module, a rock mineral testing module and a control and data analysis module, wherein the rock sample sampling module and the grinding module can automatically grind the sample required by the test, the rock element testing module and the rock mineral testing module can test the rock element and mineral content, and the control and data analysis module compares the element and mineral enrichment rules of the unfavorable geological influence area inside and outside the tunnel, and matches the result with typical unfavorable geologic body elements and mineral enrichment characteristic database to forecast the lithology change in front of the tunnel face and the occurrence characteristics ofunfavorable geologic bodies.