Light detection and ranging (LiDAR) with micro-electro mechanism system (MEMS) micromirrors at the core has the advantages of high resolution, miniaturization, and low price. However, problems still exist, including a small scanning angle and difficult construction of panoramic systems. Therefore, a novel on-chip all-silicon integrated 360° laser radar beam-mixing system is proposed in this study. A flexible beam was designed on top of the conical mirror to form a multidimensional torsion center. A combined traction mechanism of in-plane torsion and two-dimensional scanning driven by a MEMS comb driver was designed at the bottom of the conical mirror. A 360° annular space dynamic beam-mixing system was constructed with the top of the conical mirror as the rotation center and the bottom traction mechanism as the driving force. The kinematic characteristics of the beam-mixing system were analyzed by Coventor finite element software. Results show that under the driving voltage of 50 V, a single quadrangular mirror can obtain in-plane and out-of-plane twist angles of ±29.32° and ±1.8°, respectively, and form circular scanning and longitudinal fields of view covering 360° and 3.6°, respectively. The designed system solves the problem of the small field of view of MEMS LiDAR and realizes panoramic image acquisition. This research has provided a theoretical model of panoramic LiDAR for automatic driving.