Abstract: This paper analyses the basic working modes of minitype SAR on UAV for field reconnaissance, discusses the difference between SAR resolution and target separation capability. From the imaging geometry of the airborne SAR, this paper studies the influence extent to the target location precision from platform course measurement error, platform position measurement error, platform velocity measurement error, radar altitude error, bevel range measurement error of radar, and presents aviewpoint of combining the real-time location and image location. These results are very significant for the SAR design and application.