<p>Nickel-based superalloys are widely used in aerospace, energy, and chemical industries due to their excellent high-temperature strength, creep resistance, corrosion resistance, and high-temperature stability. However, hot cracks are prone to occur during welding nickel-based superalloys, which can seriously damage the structural integrity, load-bearing capacity, fatigue life, and overall safety of welded components. Therefore, this article systematically reviews the composition classification system of nickel-based superalloys and the current application of welding techniques such as fusion welding, solid phase welding, and brazing in nickel-based superalloys. It also provides an in-depth analysis of common hot cracking issues during nickel-based superalloy welding. This analysis includes the formation mechanisms of solidification cracking, liquation cracking, and ductility-dip cracking, as well as the influence of important factors such as element segregation, thermal stress concentration, and grain boundary weakening on hot cracking. In addition, this paper also sorts out the susceptibility test methods of hot cracking in nickel-based superalloys. This review provides a solid theoretical basis and technical support for the development of new nickel-based superalloy welding technology, hot cracking susceptibility test methods, and the exploration of more effective hot cracking suppression strategies.</p>