A multi-functional precious stone testing apparatus includes a portable housing, a testing unit, and an indication unit. The portable housing includes a hand-held casing and a probe casing extended from a front end of the hand-held casing. The testing unit includes a conductive probe, a sensor, and a UV light source for emitting UV light beam, so as to allow the sensor to sense the UV reflected and refracted by a testing object for determining various qualities of the testing object.