The invention provides a method for identifying whether the location of the main
reference surface of a
silicon wafer is right, with the following steps: (1) electrifying and preheating an
X ray diffractometer; loosing a knob, displacing a
detector to 26 DEG 40 MIN and locking the knob; configuring an angle presetting switch to 13 DEG 20 MIN, turning on a
vacuum pump switch, putting a sample on a testing table, opening an
X ray slot switch, and turning the sample to 13 DEG 20 MIN by hand-wheel; and fine turning the hand-wheel to maximize the indication of the pointer of an mA meter and pressing a
reset button. And (2) loosing the knob, displacing the
detector to 88 DEG and locking the knob; sticking the main
reference surface upwards to a bracket, opening the
X ray slot switch, and turning the hand-wheel till the pointer of the mA meter indicates the maximum. If the angle is in the range of 24 DEG 32 MIN plus or minus 7.5 DEG, the location of the main
reference surface is right; and if the mA meter has no response or the angle surpasses the range of 24 DEG 32 MIN plus or minus 7.5 DEG, the location of the main reference surface is improper. The method for identifying whether the location of the main reference surface of the
silicon wafer is right is simple and feasible with high accuracy.