Abstract: The defects in β-SiC epitaxial film are studied by means of etching method. The etchant used is the fused alkali hydroxide. The triangular etch pits with sharp bottom correspond to the dislocations. The perfect dislocations in β-SiC crystal are 73° dislocations and 60° dislocations. In β-SiC crystal there exists {111} boundary stacking fault formed by the contact of two β-SiC growing layer having different stacking sequences. The etching figure of the stacking fault is straight line running parallel to the 〈110〉 direction. The 60° dislocations can dissociate into two 1/6〈112〉 Schockley dislocat'ions and these two partial dislocations with a {111} stacking fault form an extensive dislocation. Three 1/6(110} stair-rod dislocations and three {111} stacking faults construct a stacking fault pyramid. Two parts of β-SiC film having positive and negative stacking sequence can produce a twin with the twin plane (111). The results of etching method and X-ray Laue method confirme the existence of the twin of this type.