The invention relates to a small-spacing tunnel excavation and middle rock reinforcement technology, which includes the following construction steps: three-lane excavation is carried out to enter a confluence section, an arch frame is densely arranged and strengthened in the confluence section, and initial liner back grouting is carried out through a small duct in the middle and goose-shaped partsof the middle rock in the three lanes; a stable bearing shell is formed around the two-lane section of the tunnel, and reverse excavation is carried out in the two-lane section from the confluence section; the reverse excavation in the two-lane section includes the excavation of the right heading pilot, the excavation of the upper left step and the excavation of the lower left step, and the initial liners of the three parts are constructed after the excavation of the three parts is completed; the inverted arch of the two-lane section is excavated, a support is constructed and the inverted arch is filled to the design elevation; and after the initial liners and the inverted arch of the double-lane small-spacing tunnel are completed, two sections of tunnel secondary liners are constructed.By grouting the middle rock through a small duct, the self-stabilizing ability of the middle rock is improved, and formation loosening and deforming is limited. Through step-by-step construction of the two-lane section, the adverse effects of blasting construction on the middle rock are greatly reduced, and the construction is safe and reliable.