Colon Nancarrow has been no doubt one of the most revolutionary composers in studying rhythmic innovation of 20th century music. He experimented rhythmic complexity extremely under the influence of Ives and Cowell and affected other significant contemporary composers such as Carter, Ligeti and later composers. The interest in rhythm is reflected well in about fifty pieces called, Studies for player piano. This paper studied the first composition for player piano, Study No. 3. It aims at the development of Ostinato and the formation process of rhythmic complexity. Study No. 3 is proceeded into two parts. First, Ostinato is the basis for structural, pitch, and rhythmic foundation. Second, perceptual polytempo was generated from various polymeter. As a result, Nancarrow's esthetic goal, temporal dissonance was created.