The Quran is a universal miracle, sent to whole humanity. The functionality of Quran in directing the lives of Muslims depends on its being understood correctly. A large proportion of the problems faced in the Muslim world, stems from the Quran being interpreted wrongly. This work aims to reveal the conspicuous mistakes in the interpretations of the Quran in the past and nowadays and to show the principles which will eliminate these misinterpretations. We should emphasize that, while determining the mistakes in the interpretations, we didn?t approach the subject from the viewpoint of any school or sect.The problems of Tafasir al-riwayah (related interpretations) are fabricated informations, carelessly quoted factitious information, the culture of Israiliyyat and wrong considerations about asbab al-nuzul (occasions of revelation). These all had been unfortunately appropriated to Islam and mostly it was Muslims who were harmed from this situation.The mistakes in Tafasir al-dirayah (opinional interpretations) generally aroused from the personality of the interpreter and his comprehension and understanding of interpretation or the method he follows.Prejudice, bigotry, imitation of the past and inconsistency are the factors which affected the interpreter negatively. We can enumerate as the other causes of mistakes: lack of complete approaches to the Quran and lack of consideration of the explanation of Sunnah and lack of consideration of asbab al-nuzul. Furthermore seeking esoteric or philosophic meanings, entering into unnecessary details and also claiming the presence of information of everything in Quran are important methodological mistakes.Modernization, occupies the Muslim world in recent centuries and efforts of reinterpretation of religious texts with some contemporary reading methods like historical, hermeneutic and anthropological are the products of those modern approaches. The intent of these methods which are suggested to be adapted to Quranic interpretation is controversial.The idea that everyone can interpret the Quran by himself without resorting to the Islamic tradition damages the universality of the Quran. Also interpreters make mistakes on controversial subjects like Nash and muhkam-mutashabih.We realize that political circumstances and dominant socio-cultural structure of the era also affects the interpreters. Trying to avoid exorbitances is essential. Furthermore avoiding the mistakes in tafsir, inversely gives drastically the principles of reliable interpretation.