<p>Based on the newly developed toroidal gyro-kinetic code GKNET, we studied the E×B staircase formation in flux-driven gyro-kinetic ITG turbulence in details. The E×B staircase was found to be long-time stationary existence with a typical wavelength delta-r around 20ρ_i, and slowly propagating outwards. When staircase happens, the turbulent transport was restricted inside the staircase region, showing a good confinement. But when global burst transport appears, the E×B staircase was found to be destroyed, and then rebuilt up. Heating effect and zonal flow excitation play important roles in the staircase formation and sustainment. In this work, we carefully discussed these issues in both linear phase and steady saturation state. </p>