This paper regards the three components of color image as a pure quaternion and presents the algorithms for color image zooming via spherical linear quaternion interpolation and algebraic trigonometric blending quaternion interpolation spline based on the research of the intrinsic correlation of color components and the nonlinear mechanism of image itself.Illustration shows that，using the new quaternion interpolation method，the clarity，brightness and more rich details on the edges of color image have greater improvements than the cases of traditional method by bicubic spline interpolation.