At present, the invert and filling construction of highspeed railway tunnels has too many procedures, which induces slow construction progress and, in the end, delays the project schedule. In the paper, the construction scheme of inverts and their filling normally adopted in the construction of doubletrack highspeed railway tunnels in Grade III rock mass is analyzed and optimized, and a new rapid technology for the invert and filling construction, which includes long trestle, slip form and separating the filling construction from the invert construction, is developed. The new construction technology developed has been applied in the construction of Naji tunnel on YunnanGuangxi railway, which increases the invert and filling construction rate from 96 m/month to 175 m/month.