Abstract: Two-point resolution with partially coherent light has been investigated in the annular aperture imaging system by using the Sparrow resolution criterion. The resolution is discussed as a function of two parameters. the spatial coherence condition of illumination and the central obstruction of an annular aperture. The ratio of the measurable to the real quantities of the point separation and the ratio of the measurable to the real quantities of the peak intensity are also analysed respectively as functions of the above two paramenters.