The percutaneous minimally invasive pedicle fixation system herein comprises a bone screw and a hook-rod, wherein the bone screw includes a positioning casing and a screw body. The positioning casing comprises securing base, an alignment casing and a screw body passage. The securing base includes a through hole at the bottom and two openings arranged opposite to each other in the wall. The alignment casing has a wall portion and a volume reduce portion, wherein the wall portion is configured with an elongate opening and the volume reduced portion is a portion with part of the wall removed to recede from the outer surface of the securing base and a guide opening formed in the volume reduced portion. The positioning casing further includes a first easy breaking portion between the alignment casing and the securing base so that the alignment casing can be removed from the positioning casing.