An insertion slot shielding mechanism for an electronic device is used to shield an insertion slot provided in an opening of a casing of an electronic device. The insertion slot shielding mechanism includes a shielding means and an elastic pushing piece. The shielding means corresponds to the opening and is slidably connected to the opening of the casing. One end of the elastic pushing piece is connected to a side wall within the electronic device corresponding to the opening of the casing, and the other end thereof is kept to abut against the shielding means. The elastic force of the elastic pushing piece allows the shielding means to be located in a position to shield the opening of the casing.