To address the collision risks in the array operation of high-altitude tethered kite power generation systems, this paper conducts a study on collision risk prediction and avoidance strategies based on trajectory dynamics. A dynamic model of the tethered kite is established in a spherical coordinate system, and a dual-layer collision detection algorithm integrating minimum bounding ellipsoids and tether segmentation discretization is proposed, thereby forming a trajectory-collision coupled detection framework. MATLAB simulation results show that the trajectory prediction error of the model is less than 4.7%. Analysis indicates that collisions occur frequently when the initial spacing is ≤75 m and become nearly zero when the spacing is ≥150 m. A pitch angle difference Δβ ≥12° can completely avoid collisions during the traction phase and reduce the collision probability in the recovery phase from 97.72% to 46.74%. An active pitch angle control-based collision avoidance strategy is proposed, and a dynamic safety interval jointly defined by spacing and pitch angle is identified.