As one kind of semiconductor material with the superiorperformance, single crystal diamond (SCD) has broad application prospects in power devices, deep space exploration and other fields. However, SCD prepared viamicrowave plasma chemical vapor deposition (MPCVD) usually contains defects, especially dislocations, seriously restrictingits electrical performance. Lateral epitaxial growth as a common defect control method in semiconductor materialsis used in SCD preparation in recent years. In this work, firstly,a pattern array was constructed on SCD seed by metal catalyzed plasma etching to create a lateral growth condition for the preparation of homogeneous epitaxial. Secondly, SCD layer was prepared by MPCVD method, and the lateral epitaxial growth process was investigated. The samples were tested by laser confocal microscopy, polarizing microscopy, Raman spectroscopyand defect density measurement. The results show that this method can stably and controllably prepare the arrays needed for patterned growth and reduce the defect density of the growth layer.