Abstract: A double-mode integral form projection unitary operator is introduced. Using the technique of integration within an ordered product （IWOP） of operators, the transformation character of the integral form projection operator is studied. The Hamihonian of double-mode quantum harmonic oscillator system with kinetic coupling is diagonalized by virtue of the integral form projection operator, and then the eigenenergy and eigenfunction of the system are accurately solved. Finally the particular case is discussed.

Key words: integral form projection operator, IWOP technique, kinetic coupling