Abstract: Thermal atomic beam sources serve as fundamental components in atomic sensing architectures, generating collimated, stable atomic beams essential for precision instruments including atomic clocks and atom interferometers. This category of sources has consequently emerged as a significant research focus in atomic beam metrology. The present work systematically examines the physical principles governing thermal atomic beam generation and reviews established collimation methodologies. A comprehensive analysis of domestic and international research developments is provided, with particular emphasis on technical implementations and performance characteristics of contemporary systems. The article concludes with a forward-looking perspective on emerging research directions and potential application domains.