Diamond from Liaoning,China was studied by synchrotron radiation and infrared spectrum.The distribution of dislocations in the speciment has been revealed.A new method to determine the orientation of crystal defects has been proposed and the orientation indexes of the dislocations in the specimen were calculated by this method.It has been found that the dislocations in the speciment are near but not precisely parallel to {111} planes,The maximum angle between dislocation and {111} plane is about 16°.Almost all the dislocations in the speciment have the same Burgers vector 1/2[101] and imply the sameness of their origination.