Abstract: At present, many problems exist in the anti-mosaic algorithm used in digital image acquisition system, such as serious interpolation pseudo-image and large computation. In order to solve the above problems, an anti-mosaic algorithm based on gradient direction was proposed to improve the demosaicking performance in practical application. Firstly, the horizontal and vertical gradients of the current pixel position were computed, and the G channel was interpolated accordingly. Then, the R channel and B channel were interpolated based on bilinear algorithm with the calibration of G channel. And this algorithm was compared with other typical algorithms from the perspective of composite peak signal noise ratio (CPSNR) and computation. The comparison results show that the proposed algorithm can consume lower computation amount and achieve excellent performance of demosaicking processing. In future, with its higher cost-effective feature, it will be used in real-time imaging and other high-tech fields.