The invention discloses a dynamic body-bias Schmitt trigger circuit which utilizes a body-bias technique to control the body-area voltages of a first NMOS transistor (10), a first PMOS transistor (11), change the threshold voltages of the first NMOS transistor (10) and the first PMOS transistor (11) and further form the Schmitt trigger circuit with a double-switching threshold value. When an input signal is a lower electric level, under the action of a second NMOS transistor (12), a second PMOS transistor (13), an NMOS body control circuit (14) and a PMOS (15) control circuit, a Schmitt trigger presents a high switching threshold value V+; and similarly, when an input signal is a higher electric level, under the action of the second NMOS transistor (12), the second PMOS transistor (13), the NMOS body control circuit (14) and the PMOS (15) control circuit, the Schmitt trigger presents a low switching threshold value V-.