The over-sampling is a novel imaging scheme for improving resolution of remote sensing scanning images. If the scheme is employed by the infrared search and track system, it is necessary to analyze the effect of the over-sampling on the point target detection performance. The characteristics of over-sampling imaging are compared to those of the standard sampling with respect to the scanning imaging principle. Based on degradation of high-resolution image, a method of scanning image simulation is proposed. The scanning images including objects are simulated and processed by a typical single-frame target detection algorithm, and the detection performance of the two sampling schemes is analyzed. Experimental results show that under the same conditions, the point target detection performance of the over-sampling scheme is better than the standard sampling. The scanning image of standard sampling for target is generally a 1×1 point, while the over-sampling scheme creates pixel-clutter for target. The characteristic can improve the target detection performance further.