The invention discloses a preparation method of a non-volatile memory based on a metallic oxide thin film transistor, implemented through the following steps of: a, preparing and patterning a metal or semiconductor layer as a floating gate electrode on a substrate; b, depositing a first insulating layer as a tunneling layer on the floating gate electrode; c, depositing a metallic oxide semiconductor thin film on the first insulating layer and patterning to form a first active layer and a second active layer; d, continuously depositing a second insulating layer and a metal layer on the second active layer, patterning the first metal layer as a gate electrode, and patterning the second insulating layer as a gate insulating layer by means of taking the gate electrode as a mask and using an automatic alignment method; e, depositing and patterning a third insulating layer as a passivation layer; f, depositing and patterning a second metal layer as source and drain electrodes on the third insulating layer. The method provided by the invention has simple technology.