Among 3D reconstruction techniques, most of them are for still objects. We design and implement a ready-to-use system for 3D trajectory reconstruction of high speed moving objects. Hardware camera synchronization, multi-threading programming, 3D reconstruction camera model (rather than pin-hole model) are used for enhancing performance in speed and in accuracy to fulfill the requirement in high speed environment. This implementation is especially useful for computer-assisted evaluation in game study, sport medicine, and physical therapy.