A side-covered axial flow filter, and characterized in that the side-covered axial flow filter comprises: a housing having an axial direction; a radial direction being perpendicular to the axial direction; an inlet; an outlet; the inlet and the outlet respectively formed on two opposite ends of the housing along the axial direction; an installation opening formed in a side surface of the housing along the radial direction and communicating with the inlet and the outlet; a clamping surface defined as an inner surface of the housing, and the outlet formed through the clamping surface; two first pushing panels protruding from the inner surface of the housing, opposite to each other, and being adjacent to the outlet; the two first pushing panels and the installation opening respectively disposed on two opposite sides of the housing along the radial direction; a filter core mounted in the housing; a filter frame mounted on an end of the filter core along the axial direction, mounted in the housing, being adjacent to the outlet of the housing, and having two limiting ribs protruding from the filter frame, opposite to each other; each one of the two limiting ribs protruding through a portion between a respective one of the two first pushing panels and the clamping surface, and having an outer pushing part protruding toward the outlet of the housing; an inner pushing part protruding toward the inlet of the housing; a sealing unit mounted on the filter frame and clamped between the filter frame and the housing;and a side cover detachably mounted on the housing, covering the installation opening, and pushing the filter frame toward the outlet of the housing, the side-covered axial flow filter characterized in that the outer pushing part protruding toward the outlet of the housing abuts said clamping surface and the inner pushing part protruding toward the inlet of the housing abuts said respective one of the two first pushing panel s; wherein a portion where the inner pushing part abuts the respective one of the two first pushing panels is radially outward with respect to a portion where the outer pushing part abuts the clamping surface of the housing. a housing having an axial direction; a radial direction being perpendicular to the axial direction; an inlet; an outlet; the inlet and the outlet respectively formed on two opposite ends of the housing along the axial direction; an installation opening formed in a side surface of the housing along the radial direction and communicating with the inlet and the outlet; a clamping surface defined as an inner surface of the housing, and the outlet formed through the clamping surface; two first pushing panels protruding from the inner surface of the housing, opposite to each other, and being adjacent to the outlet; the two first pushing panels and the installation opening respectively disposed on two opposite sides of the housing along the radial direction; an axial direction; a radial direction being perpendicular to the axial direction; an inlet; an outlet; the inlet and the outlet respectively formed on two opposite ends of the housing along the axial direction; an installation opening formed in a side surface of the housing along the radial direction and communicating with the inlet and the outlet; a clamping surface defined as an inner surface of the housing, and the outlet formed through the clamping surface; two first pushing panels protruding from the inner surface of the housing, opposite to each other, and being adjacent to the outlet; the two first pushing panels and the installation opening respectively disposed on two opposite sides of the housing along the radial direction; a filter core mounted in the housing; a filter frame mounted on an end of the filter core along the axial direction, mounted in the housing, being adjacent to the outlet of the housing, and having two limiting ribs protruding from the filter frame, opposite to each other; each one of the two limiting ribs protruding through a portion between a respective one of the two first pushing panels and the clamping surface, and having an outer pushing part protruding toward the outlet of the housing; an inner pushing part protruding toward the inlet of the housing; a sealing unit mounted on the filter frame and clamped between the filter frame and the housing;and two limiting ribs protruding from the filter frame, opposite to each other; each one of the two limiting ribs protruding through a portion between a respective one of the two first pushing panels and the clamping surface, and having an outer pushing part protruding toward the outlet of the housing; an inner pushing part protruding toward the inlet of the housing; an outer pushing part protruding toward the outlet of the housing; an inner pushing part protruding toward the inlet of the housing; a sealing unit mounted on the filter frame and clamped between the filter frame and the housing;and a side cover detachably mounted on the housing, covering the installation opening, and pushing the filter frame toward the outlet of the housing, the side-covered axial flow filter characterized in that the outer pushing part protruding toward the outlet of the housing abuts said clamping surface and the inner pushing part protruding toward the inlet of the housing abuts said respective one of the two first pushing panel s; wherein a portion where the inner pushing part abuts the respective one of the two first pushing panels is radially outward with respect to a portion where the outer pushing part abuts the clamping surface of the housing.