This paper presents a miniature multispectral camera and its application in machine vision. Differ to conventional camera, the multispectral camera can capture image with high spectral resolution. First, the design of the multispectral camera is introduced. It consists of a Digital Micro-mirror Device (DMD) sandwiched by two optic gratings. Then, optical analysis is carried out, which demonstrates the spectral decomposition of an image. Next, two simulation examples are presented. The first example compares the difference among four clays with close colors. The second example compares two sets of similar food: one set is real while the other set is fake. The simulation examples demonstrate that the multispectral camera is capable of identifying detailed spectral information that conventional camera cannot. It is therefore believed that the multispectral camera will find some practical applications soon.