The present invention discloses a high-ground-stress weak surrounding rock tunnel excavation construction method. A weak surrounding rock tunnel under construction is excavated and constructed by multiple segments from back to front along a tunnel lengthwise extension direction. The method comprises a first step of rock mass strength and surrounding rock internal maximum ground stress testing; a second step of surrounding rock extrusion-type large deformation level determination; a third step of tunnel deformation allowance determination, determining the deformation allowance according to a determined extrusion-type large deformation level; a fourth step of tunnel excavation construction, carrying out excavation construction on the current constructed segment according to the determined deformation allowance; a fifth step of carrying out excavation construction on the following segment; and a sixth step of repeating the fifth step till a tunnel excavation construction process is completed. The method provided by the present invention is simple in procedure, reasonable in design, convenient to construct and excellent in using effect, the tunnel excavation deformation allowance is determined according to the high-ground-stress weak surrounding rock extrusion-type large deformation level, the tunnel excavation construction process can be conveniently and quickly completed, and the construction process is safe and reliable.