As a promising manufacturing technology, laser cladding has been widely used in industry for component repair, surface modification, and additive manufacturing. In a laser cladding system, the laser cladding machining head is its key component, which can realize the precise coupling between the laser beam, the cladding material and the molten pool on the surface of the substrate and continuously form the cladding layer. The laser cladding machining head has a built-in optical lens group, which is mainly used for transmission, transformation, and focusing of the laser beam, and the beam can be processed according to different processing requirements. The processed beam develops specific focusing properties such as spot size, spot shape, energy distribution and depth-of-focus characteristics. In general, the focusing characteristics of different light sources vary greatly, and the focusing characteristics directly affect the quality of the cladding layer and the formed part through optical material coupling. This requires matching process parameters, including laser power, scanning speed, feed rate and overlap rate. This article mainly analyzes the influence of the laser cladding machining head‘s focusing performance on the cladding forming process, and reviews the design of the machining head and the development of its forming process. Specifically, it includes the influence of spot shape, spot size, spot energy distribution, laser power, light source characteristics, etc. on material deposition speed, cladding material utilization efficiency, and cladding layer quality.