The classification of etch pits formed by hydrogen plasma etching on heteroepitaxial diamond has been done by cross-sectional transmission electronmicroscope (TEM). We demonstrated that the origin of etch pit was mainly [001] threading dislocation. From invisibility criterion of dislocation contrast in TEM observation, this dislocation was identified as edge and 45 degrees mixed dislocation. The correlation between dislocation types and etch pit shape was discussed. (C) 2016 Elsevier B.V. All rights reserved.