Divine knowledge is one of the most complicated problems of the attributes dealth with in theology. Molla Sadra, relying on his philosophical principles in cluding the rule of the pure essence, basit al-haqiqah, has presented a new theory on Divine knowledge.On this basis, God in His essence knows all things in brief, in such a manner that by that brief and pure knowledge all things are known for Him in details. Sadra, furthermore, on his philosophical principles, support the essentiality and necessity of Divine knowledge. Although in Sadra`s view Divine knowledge of the creatures is essential and pure, in accordance to multiplicity of His creatures, one can agree with degrees of the knowledge called attention (inayat), decree (qaza), destiny (qadqr), pen (qalam), table (lauh) and the book of existence.