To investigate the effect of Si content on the high-temperature corrosion resistance of Ni-Cr-Mo alloy cladding layers, four cladding layers with different Si contents were prepared by laser melting technique. The corrosion resistance of the four cladding layers was tested by the mass loss method in a simulated waste-to-energy corrosive environment at different temperatures. Through the analysis about the characteristics of corrosion products of four cladding layers generated at 600 and 650 °C, it is found that the Si addition is beneficial to the stability of the Cr-rich oxide in the corrosion products. The adhesion of Cr-rich oxide to the substrate can also be enhanced through the pinning effect, thus effectively improving the corrosion resistance of cladding layer. However, excess Si addition has the negative effect. When the temperature is above 600 °C, the cladding layer with 3wt% Si shows the optimal corrosion resistance. This phenomenon is attributed to the formation of SiO₂ protective layer in the corrosion layer, which improves the corrosion resistance of cladding layer with 3wt% Si. Because of the small Si addition amount and the severe Si segregation, the effective SiO₂ protective layer cannot be formed in the cladding layers with 1wt% and 5wt% Si, respectively.