Color filter is the key component of the detector of space optical-remote-sensing camera. It is used for multispectral band-pass filtering and for the encapsulation of detector. Color filter is more complicated than the panchromatic or monochromatic filter. Physical dimension of filter substrate, light window size, black layer outline size and on-filter alignment mark are the feature sizes of a color filter. This article gives the designing and calculating method of these feature sizes. Analysis of influences on detector and camera resulting from the designing and manufacturing error is also proposed, such as filter-and-die alignment precision, detector butting on focal plane assembly, and spectral response characteristic of the camera. Finally a designing and application example of a color filter on some camera is given.