焊接电弧中含有丰富的光谱信息，利用这些信息对焊接电弧这一复杂的物理现象进行测试（或称诊断）和控制，是提高和发展焊接技术的一种非常有效的方法，具有重要的理论和实际意义。文章论述了这方面 研究的进展，阐明了电弧光谱信息的测控原理，介绍了电弧光谱信息在电弧诊断，电弧气氛监控，弧焊区成像，特别是近年来在脉冲MIG焊熔滴过渡控制等方面的应用情况。同时，还介绍了这一技术在等离子体现象中的一些重要应用，并总结出几点基本看法，指出了它的发展方向。

Welding arc is full of spectral information. Studying and utilizing the information to diagnose and control the welding arc is the most effective way to develop and improve the welding technology. Furthermore, it can be used to study and control other relative physical phenomena (such as gaseous plasma, laser processing plasma, underwater plasma arc, etc.). It is of great theoretical and practical significance. This paper has summarized the developing situation of the research on this field, expounded the principle of measurement and control by welding arc spectral information, described the application situation of welding arc spectral information, for example, the arc diagnosis, monitoring of arc atmosphere, imaging of arc welding region and control of droplet transfer in pulsed MIG welding, etc. At the same time, the authors have also introduced the application of arc spectral information in the development of plasma technology, such as in the development of plasma torch with carbon electrode and in the judgement of local thermodynamic equilibrium of underwater plasma arc. At last the authors have put forward some points of basic view on the technology and pointed out its developing direction.