In order to investigate the effect of TiC on the microstructure of 304 stainless steel fusion cladding layers, 304 fusion cladding layers without and with varying TiC contents were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results demonstrate that the solidification model of 304 stainless steel is the FA model. The 304 stainless steel microstructure is austenite and ferrite, and the cladding layer is composed of planar, columnar, and equiaxial crystals, from bottom to top. The TiC is primarily distributed in small round and square grains, with a minor amount present in the agglomerated state. The 10% TiC cladding layer comprises TiC and Cr23C6, with the grains arranged in an isometric crystal morphology. The lower and middle layer grains exhibit strong parallelism within the needle structure, while the upper layer grains display coarsening, however, the needle parallelism is not evident. The 20% and 30% TiC cladding layers have been observed to contain an α-Fe martensite phase. The grains of the 20% TiC cladding layer are observed to be large islands, granular, and rod-like, with the grains undergoing grain refinement from bottom to top. The morphology of the 30% TiC cladding layer is granular and rod-like, from the bottom to the top, the grains exhibit slight coarsening. The effect of TiC on the microstructure mechanism can be described as follows: TiC addition can facilitate heterogeneous nucleation and impede grain growth, thereby promoting microstructure refinement. The TiC content in the lower layer of the fusion cladding is relatively low, the TiC of re-nucleation after dissolution and unmelted TiC, which form fine grains as nuclei. In the upper layer of the cladding, the TiC content increases, the proportion of grains reliant on the nucleation of unmelted TiC particles increases, and the formation of grains is coarser than in the lower layer. The addition of TiC powder alters the morphology of the grains in the cladding. With an increase in TiC content, the cladding layer appears to have a martensite phase, and the content and number of holes in the upper layer increase with elevation of the TiC. The study can provide insight into the organization morphology change principle of 304/TiC composite coatings.