The invention discloses a pushing system for U-turn pushing construction of a shield machine in a metro tunnel. The pushing system is characterized in that a base plate bedding is arranged in an end well so as to cover an upturning beam, and the base plate bedding comprises a lower bedding formed by paving padding broken stones and an upper bedding formed by paving medium coarse sand; a steel plate layer is paved on the upper bedding and is taken as a carrier for the shield machine; a shield machine receiving frame is arranged and is formed by welding a steel base plate at the bottom of a rectangular framework; a pushing mechanism is arranged and is constituted by arranging pushing hydraulic oil cylinders at two sides of the shield machine receiving frame; and a pushing counter-force frame is fixedly arranged on a steel plat layer. According to the invention, the U-turn construction for the shield machine can be ensured to be performed rapidly and safely under a limited field condition.