We study the forming process of TiOx resistance random access memory (RRAM).The transparent TiOx thin films with high refractive index (mean value is about 2.23in the visible range) and low extinction coefficient (mean value is about 0.0042in the visible range) are fabricated by changing the oxygen partial pressure via magnetron reactive sputtering.Then,we obtain the RRAM characteristics that resistance could be switched by constructing Cu/TiOx/Al sandwich structure.Then we realize the mul ti-step unsufficient forming by using different forming voltages and currents.Through the dif ferent I-V fitting on different steps of the unsufficient forming,we study the electron transmission mechanism of the transparent TiOx in the forming process further.The re sults show that the electron transmission mechanisms of transparent TiOx d uring forming change obviously from Schottky emission to Fowler-Nordheim tunnel,direct tunnel,and Ohmic transmission finally .