A heat dissipation system for an optical module, comprising a circuit card on which at least one optical module is mounted, wherein the optical module comprises a housing and a laser disposed inside the housing; a first heat dissipation apparatus is fixedly disposed on the circuit card; a planar heat dissipation window provided in an area that is above the laser and on the housing of the optical module; and the first heat dissipation apparatus is configured to perform heat dissipation on the heat dissipation window; wherein the heat dissipation window is a heat sink fin in a cross structure, wherein the heat sink fin comprises multiple first toothed bars disposed at intervals in a first direction along the window plane and multiple second toothed bars disposed at intervals in a second direction along the window plane, where the second direction is perpendicular to the first direction; and the second toothed bars are located on surfaces of the first toothed bars, and the second toothed bars and the first toothed bars are disposed in a cross manner, wherein the multiple first toothed bars are disposed parallel to each other; and the multiple second toothed bars are disposed parallel to each other, whereby discharge paths are formed by gaps between the first toothed bars and the second toothed bars, wherein the first heat dissipation apparatus is a piezoelectric film fan, wherein the piezoelectric film fan comprises a hollow body, a film, and a piezoelectric plate, and the piezoelectric plate and the film are fixedly connected to form a piezoelectric structure; and the piezoelectric structure is disposed inside a hollow cavity of the body, and a gap exists between the piezoelectric structure and an inner wall of the body; and a first opening is provided on a surface on a side, corresponding to the piezoelectric plate, of the body; a nozzle is provided on a surface, opposite to the first opening, of the body, and the nozzle faces to the heat dissipation window; and the piezoelectric plate is configured to be electrically connected to an alternating current. wherein the heat dissipation window is a heat sink fin in a cross structure, wherein the heat sink fin comprises multiple first toothed bars disposed at intervals in a first direction along the window plane and multiple second toothed bars disposed at intervals in a second direction along the window plane, where the second direction is perpendicular to the first direction; and the second toothed bars are located on surfaces of the first toothed bars, and the second toothed bars and the first toothed bars are disposed in a cross manner, wherein the multiple first toothed bars are disposed parallel to each other; and the multiple second toothed bars are disposed parallel to each other, whereby discharge paths are formed by gaps between the first toothed bars and the second toothed bars, wherein the first heat dissipation apparatus is a piezoelectric film fan, wherein the piezoelectric film fan comprises a hollow body, a film, and a piezoelectric plate, and the piezoelectric plate and the film are fixedly connected to form a piezoelectric structure; and the piezoelectric structure is disposed inside a hollow cavity of the body, and a gap exists between the piezoelectric structure and an inner wall of the body; and a first opening is provided on a surface on a side, corresponding to the piezoelectric plate, of the body; a nozzle is provided on a surface, opposite to the first opening, of the body, and the nozzle faces to the heat dissipation window; and the piezoelectric plate is configured to be electrically connected to an alternating current.