Image smoothing will lead to boundaries blurred, so image must be sharpen the edges of the image becomes clear. Traditional way of sharpen picture quantity has many problems. Tubbs used Beta function B (α, β) to sharpen picture, but how to determine the Beta parameters is still a complex issue. This paper describes the use of quantum genetic algorithm for nonlinear transformation parameters α and β, which adaptive to achieve gray-scale image enhancement. Finally, through simulation experiments verify the effectiveness of genetic algorithms to sharpen image.