Abstract: Plasma, plume, sound, radiated light, electricity and other signals will appear in the laser welding process. By studying these signals and correlating them with the stability of the welding process and welding defects, real-time quality monitoring of laser welding process can be achieved. Through the introduction of laser welding characteristics and the comparative analysis of monitoring methods, it was concluded that the multi-sensor fusion technology had the advantages of rich monitoring information and high accuracy in welding status and defect prediction. According to the types of sensors compounded by quality monitoring system of laser welding process，the multi-sensor fusion technology was divided into four categories， multi-vision sensor, multi-optical sensor, optical and vision sensor, and other composite technology. Different multi-sensor fusion technologies were reviewed, realizing the advantages of optical and vision sensor composite technology that were sensitive to changes in welding status, fast sampling speed, and rich collection of information. Meanwhile, several advanced multi-sensor fusion products which could be applied to laser beam welding were introduced. Finally, the disadvantages and the future development direction of multi-sensor fusion technology were clarified.Highlights: (1) Characteristics and comparative analysis of different multi-sensor fusion technology were carried out.(2) For commercial multi-sensor fusion technology products, its principle was analyzed and its application example was introduced.