The invention discloses a humidifier and a fuel cell humidification system.The humidifier comprises a shell, a core and a spoiler, the shell is provided with a cavity, a first inlet, a second inlet and an outlet, and the first inlet, the second inlet and the outlet are all communicated with the cavity; the shell is provided with a first inlet and an outlet, the first inlet and the outlet are oppositely arranged along the length direction of the shell, the outlet is arranged adjacent to the first inlet, the core body is arranged in the cavity, the outer peripheral surface of the core body and the inner peripheral surface of the shell are arranged at an interval, the core body is arranged adjacent to the second inlet, and the core body is arranged in the cavity. The core body is arranged in the cavity, the cross section area of the core body is gradually increased in the direction towards the first inlet, and the spoiler is arranged in the cavity and arranged at the end, close to the outlet, of the core body. The humidifier has the advantages of being simple in structure, low in cost, good in humidifying effect and the like.