The invention provides an ion funnel and a mass spectrometric detection system. The ion funnel comprises M annular electrodes that are provided with the same outer diameter and are coaxially arranged at the same interval; the inner diameters of the annular electrodes are decreased in sequence from the first annular electrode to the M(th) annular electrode; the ion funnel also comprises a first direct current power supply, a second direct current power supply, a first radio frequency power supply and a second radio frequency power supply; the first direct current power supply and the second direct current power supply are connected with the first annular electrode and the M(th) annular electrode respectively, and the M electrodes are connected in series by the first direct current power supply and the second direct current power supply through a voltage-dividing resistor; the first radio frequency power supply is connected with the first annular electrode, the (1+N)th annular electrode until the (1+2N)th annular electrode in parallel; the second radio frequency power supply is connected with the second annular electrode, the (2+N)th annular electrode until the (2+2N)th annular electrode in parallel; the (N-1)th radio frequency power supply is connected with the (N-1)th annular electrode, the (N-1+N)th annular electrode until the (N-1+2N)th annular electrode in parallel; and the Nth radio frequency power supply is connected with the Nth annular electrode, the (N+N)th annular electrode until the (N+2N)th annular electrode in parallel. According to the ion funnel, the ion transmission efficiency is improved, and in particular, the transmission efficiency of ions with small mass number is improved.