This paper shows some simulation analysis on stitching overlap threshold of strip images for mul-ti-strip stitching model in agile remote sensing imaging. The mission model and geometric degradation model are proposed for multi-strip stitching imaging, and the criterion of overlap region width threshold is presented. Against the nadir strip, we analyze the overlap threshold of different scene types and explore the threshold varia-tion affected by the changes of ground sample distance (GSD). For the agile strip, the effect of pitch angle and roll angle on overlap threshold is analyzed. The simulation result shows that, at 0.46-meter GSD value, the over-lap threshold is more than 28 pixels for 6 scene types, and it is even beyond 31 pixels for the airport and island. The statistical characteristics of threshold perfect match the 3σ guidelines in normal distribution, which has proved the reliability of the solution of overlap threshold. In nadir imaging, GSD has little effect on the overlap pixel threshold at image plane, but has a great effect on overlap distance threshold at ground plane. In agile strip, with larger pitch angle and roll angle, the overlap threshold will increase significantly, which means that the ge-ometric degradation is more powerful to the threshold than the GSD variation. By analyzing the stitching overlap threshold of the strips, we give a meaningful suggestion to the mission planning of high resolution remote sens-ing imaging by agile satellite.