The utility model discloses a construction cross section coordinates in four lane tunnel subsections in single hole that are applied to III grades of country rocks, including being located the first pilot tunnel of upper left side, being located the second pilot tunnel of upper right side and being located the third pilot tunnel of right downside, the region of inboard of the preliminary excavation hole that forms of first pilot tunnel, second pilot tunnel and the third pilot tunnel body for waiting to dig the region. First pilot tunnel and second pilot tunnel between be provided with interimsupport, interim upper end of supporting and steel bow member fixed connection, the interim bottom entry that supports is to wait to dig the region in. The third pilot tunnel and wait to dig the inclined plane for having a grade alpha between the region, just the inclined plane on be provided with spray layer and strut. This section piecemeal is few, and the interim support that needs is also few,has not only improved the factor of safety of construction, moreover the construction cycle is reduced.