Tidal-current turbine which is vertical-axis type has been proposed by many researchers as a power generation with renewable energy resources. The main disadvantage of vertical-axis type is low performance compared with horizontal-type. This study focuses on how to enhance the performance by maintained lift capability with modified an original foil profile of NACA 63(4)021 to be a tubercle profile. The foil is simulated with Computational Fluid Dynamics software with some variations on angle of attack. Tubercle in leading-edge foil section can delay static stall angle and increase lift performance in high angle of attack. Since the vertical-axis turbine is rotated in 360o that mean its angle of attack change continuously in each position of rotation then it will experience a dynamic stall. Therefore, vertical-axis turbine which the foil profile modified with tubercle become a good chance to increase the range operation of extracting energy in dynamic stall condition by maintain the lift performance in high angle of attack.