The effects of plasma velocity profiles, that are not monotonous but with maximum/minimum, on plasma instability and transport in an internal transport barrier (ITB) are studied. Ion temperature gradient (ITG) instability is investigated. Results from the gyro-kinetic theory are presented. It is found that the mode structures and stability prop The effects of plasma velocity profiles, that are not monotonous but with maximum / minimum, on plasma instability and transport in an internal transport barrier (ITB) are studied. Results from the gyro-kinetic theory are presented. It is found that the mode structures and stability prop