The spatial-filtering velocimetry method has the advantages of having a simple structure, good stability, and strong applicability. However, the traditional linear-array Charged Coupled Device (CCD) spatial-filtering velocity measurement method requires that the direction of the CCD array be the same as the direction of motion of the object whose velocity is to be measured . Therefore, this method is not suitable for measuring complex flow fields. To solve this problem, this study proposes a spatial-filtering velocity- measurement method based on an area-array CCD camera. A series of area-array CCD output images were collected from the measurement area. Interlaced sampling was performed in the horizontal and vertical directions of the image to simulate the multi-slit spatial-filtering characteristics, and an optical non-contact measurement of flow particle velocity around an obstacle was realized. Moreover, regarding the characteristics of the power spectrum density of complex flow fields, using an energy center-of-gravity correction spectrum improves system measurement accuracy. The system was calibrated by adjusting the speed of the conveyor to achieve measurements at different speeds with an average error of less than 4%. In addition, the debris-flow velocity-field distribution simulated with glass sand was also measured using this system. Finally, the influence of spatial period and duration on the measurement results was discussed, which demonstrate that the measured velocity reaches a plateau for sampling over 0.5 s and the spatial resolution is improved to be 1.28 mm.