The purpose of tort law focuses on the damages of individuals for the rights infringement that trespasser or wrongdoer is indebted to compensate such as property damage and human injury involving both physical and psychological harm. However, There are still numerous controversial issues in the aspect of tort law. One of the most interesting problems is ùMental injuryû. International academic legal field questions that what the suitable level of compensation for psychological injury is. This research will offer the model of the extent of damages for mental injury and, moreover, compare and contrast this level in selective countries which may be highly influence upon legal systems around the world both ùCommon Lawû legal system countries namely the United Kingdom and the United States of America and also ùCivil Lawû legal system countries namely France, Germany, Switzerland, Japan and Thailand. Finally, this paper will evaluate the proper extent which the level of mental injury damages called ùDistress Levelû might be the most appropriate extent of this compensation.