The invention provides a tunnel loose block fracture zone building method. An explosive drilling hole is respectively formed in two side walls of the tunnel; the height of a blast hole is the same as the height of a receiver; then micro-vibration is conducted after all elements are well arranged; a hole is drilled in a tunnel face by an advanced horizontal drilling machine; the rest holes are all outwardly drilled except the center drilling hole drilled along an axis of the tunnel; an annular various-pit drilling method is employed for excavation; water is discharged from an inner cave during construction; water drainage slopes are preserved in the longitudinal and transverse direction during excavation of the upper, lower and middle parts; water is led to the axial middle part of the tunnel, so the arc wall foot is depowered and water on the work surface can be instantly pumped to a water pit; the cave is kept dry and immersion damage to an inverted arch and a wall foundation soil layer by accumulated water can be prevented; and then each part is excavated in a circular way. Deficiencies existing in a super-support are analyzed; parameters affecting support effect is researched and adjusted on the basis of the original design scheme; optimum parameters are determined via tests and great supporting effect is achieved; and scheme changes are avoided and cost is reduced and construction progress is ensured.