<p>The motorized spindle is a critical component in advanced manufacturing equipment, and its performance directly determines the accuracy and efficiency of CNC machine tools. This paper provides a systematic review of recent technological advances in motorized spindles, with a focus on bearing systems, thermal characteristics, and intelligent fault diagnosis. By surveying mainstream products and relevant research, this study summarizes the current state of spindle bearing configurations, lubrication methods, preload strategies, thermal error control approaches, and diagnostic technologies. The results indicate that the bearing system remains the key factor limiting spindle speed and stiffness; thermal error control strategies are evolving toward the integration of intelligent compensation models with active cooling; and fault diagnosis techniques are progressing from high prediction accuracy to enhanced reliability. In summary, high-performance bearing systems serve as the foundation of spindle design, efficient thermal error control is essential for sustaining performance, and intelligent fault diagnosis represents an inevitable trend for future development. This review provides valuable insights for spindle design optimization and engineering applications.</p>