Abstract: (WMoCrTa)Si2 coating was prepared through a two-step process involving slurry sintering followed by halide-activated pack cementation, with silicide powders as the raw materials. Four layers comprise the final coating: a porous high-entropy silicide layer, a chromium-tantalum silicide layer, a TaSi2 interlayer, and an innermost Ta5Si3 layer with an overall thickness of 186 μm. Under static air oxidation at 1400 ℃, the coating can protect the Ta substrate for over 14 h, with its mass gain curve showing a three-stage behavior (slow growth, rapid gain, gradual stabilization). In the initial stage, a dense SiO2 scale formed rapidly; Cr preferentially was oxidized to Cr2O3, which further reacted with Ta2O5 to form CrTaO4, and their synergy enhanced the coating’s stability and oxygen-blocking ability. The coating’s protective performance finally degraded due to SiO2 spallation and internal pore proliferation.