The invention discloses a differential current sampling circuit. The sampling current input end of the circuit is connected with the drain of a second NMOS transistor; the voltage output end of the circuit is connected with the source of a first NMOS transistor; the control pulse input end of the circuit is connected with the gate of the first NMOS transistor; the source of a first PMOS transistor is connected with a voltage source, the drain of the first PMOS transistor is connected with the drain of a third NMOS transistor, the gate of the first PMOS transistor is connected with the drain of a fourth NMOS transistor, the drain of the first NMOS transistor and the gate and the drain of the second PMOS transistor; the source of the second PMOS transistor is connected with the voltage source; the gate of the second NMOS transistor is connected with the gate of the third NMOS transistor and the gate of the fourth NMOS transistor; and the source of the second NMOS transistor, the source of the third NMOS transistor and the source of the fourth NMOS transistor are all grounded. The MOS transistor circuit is adopted, so advantages of small integrated circuit occupied area, process compatibility and fast speed can be realized.