According to the extensive demand of two-dimensional (2D) bar code devices on the market, we studied the QR-code detection and recognition technology based on mobile DM642. This study proposes an algorithm based on position detection patterns, which have the nesting feature between the contour and the connection of area ratio. It locates the QR-code in order to solve the problem of skew and distortion of the image in embedded intelligent devices. Then, it precisely positions the four angular point coordinates of the QR-code by the method of linear approximation, and the QR-code is reconstructed by the principle of inverse perspective transformation and rotation correction. Finally, it obtains the whole 2D code "01" matrix by the grid sampling based on the reconstructed image, which is convenient for the decoding of QR-code. We transplanted the algorithm to the DM642 to run. It can effectively solve the image inclination and distortion problems and decoding effect is normal.