The problems of splintering and crosstalk limit the development of indium antimonide (InSb) focal plane detectors to larger array sizes and smaller pixel pitches. The experimental results of an InSb focal plane detector using discrete photosensitive pixels are reported. An InSb infrared detector with an array size of 320×256 and a pixel pitch of 30 μm is prepared, and the average signal response value is measured to be 441.112 mV and the average noise value is measured to be 1.729 mV. This array is discrete, which alleviates the problems of splintering and crosstalk, and has high reliability and high filling rate. Compared with the method of bonding silicon wafers and then etching to form discrete pixels, this method does not have the absorption loss of incident light information by silicon wafers, and the manufacturing process is simple.