An approach is proposed to reduce the tracking jitter of the extended target in boost phase for plume tracker in a photoelectric acquisition, tracking, and pointing system. The characteristics of the vehicle imaging are analyzed and the causes of jitters are identified. The target moving direction and its principal axis are combined to calculate the optimal frontal direction. A contour smoothing method based on the chord-arc ratio filtering is introduced to obtain a preliminary extraction point with lower jitters. Then a fine tracking point extraction method based on the minimal inscribed circle of contour after filtering is presented. Experimental results confirm that the proposed method significantly improves the tracking precision and stability. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.