The invention discloses a shift register, a gate drive circuit unit, a gate drive circuit and a display. The gate drive circuit comprises the gate drive circuit units in multi-level cascade, each gate drive circuit unit comprises shift registers in multi-level cascade, the plurality of shift registers share a pull-down module, and consequently the number of transistors in the circuit is decreased, and circuit yield is increased. The gate drive circuit can be used for driving a display panel; due to reduction of the transistors in the circuit, size of the circuit is reduced, and manufacturing of a narrow-frame display is benefited; in addition, cost is reduced, circuit yield is increased, and display stability is improved.