To determine the direction of a rotational speed and to calculate the value of the rotational speed in remote angular-velocity measurement with the spatial filtering technique,it is necessary to exactly identify the location zone of measured-object rotation center.Therefore, a method of determining the rotation center based on Double Differential Spatial Filtering Sensor (DDSFS)was proposed according to the principle of spatial filtering velocimetry. The DDSFS constructed by multiple photovoltaic cells consists of two Differential Spatial Filters (DSFs),which outputed two quasi-sinusoidal signals with the central frequencies of f1 and f2.By moving the DDSFS,a coefficient j could be calculated by using two groups of central frequencies before and after moving the DDSFS.Then,the location zone of the rotational center could be distinguished depending on the sign of the coefficient j and the relative relation between f1 and f2.The achieved results show that j<0 represents the location zone of the imaged rotation center O′ to be between DSF1 and DSF2,and that j>0 with f1>f2 indicates the location zone of the imaged rotation center O′ to be below the DDSFS,and that j>0 with f1