The invention relates to a tunnel-type disposable sterile vaginal dilator. The tunnel-type disposable sterile vaginal dilator comprises an upper dilation vane, a lower dilation vane, a push rod, an arc light guiding column, a light source and an assisted dilation mechanism, wherein an adjusting mechanism is arranged at the top end of the push rod; the arc light guiding column and the light source are arranged on the lower dilation vane; a light output end of the light source is supported against the arc light guiding column; the upper dilation vane is provided with an exhaust structure used for exhausting smoke in the vaginal cavity; the exhaust structure consists of a connecting pipe and an exhaust groove; slide rails are arranged on two sides of the exhaust groove, slide ways matched with the slide rails are formed in the upper dilation vane, and the exhaust structure is detachably connected with the upper dilation vane due to matching of the slide rails and the slide ways; the assisted dilation mechanism consists of a first dilation piece and a second dilation piece, either of the first dilation piece and the second dilation piece consists of a dilation part, a spacing part and an assembly part; the first dilation piece and the second dilation piece are detachably connected by means of matching of the assembly parts, and the dilation parts are folded or unfolded due to matching of the spacing parts. The tunnel-type disposable sterile vaginal dilator has the advantages of reasonable structure design, convenience in use and good reliability.