The invention discloses a method for advanced compaction grouting reinforcement of a spongy stratum suitable for a shallow-buried excavation tunnel. The method comprises the following steps that: a stratum compaction performance of penetration of a tunnel into a spongy stratum is tested by the experiment and thus compaction degrees of the stratum under different grouting pressures as well as mechanical and anti-penetrability performances corresponding to different compaction degrees are determined; influences on tunnel excavation stability by the different stratum compaction degrees and grouting reinforcement ring thicknesses are analyzed, so that a target grouting pressure and a grouting reinforcement ring thickness are determined; a maximum expansion radius of an expansive soil geotextile bag and an earth surface grouting hole arrangement interval are determined; a grouting pipe with the expansive soil geotextile bag is made; grouting hole drilling work is carried out on the earth surface and the grouting pipe with the expansive soil geotextile bag is inserted after the grouting holes reache a predetermined depth; grouting is carried out by using a quick-setting grouting materialand grouting is stopped when the grouting pressure reaches the target grouting pressure; the gaps between the grouting pipe and the grouting holes are filled and sealed; and grouting work of all grouting holes is completed.