The invention provides an optimizing method of the electrical transport property of an ultrathin lanthanum nickelate film. The method comprises following steps: firstly, an SrTiO3 substrate is subject to surface step treatment, and a substrate with the TiO2 surface step is obtained; secondly, a pulse laser method is adopted to deposit an LaAlO3 film on the substrate obtained in the first step, and two-dimensional electron gas appears in the LaAlO3/SrTiO3 interface; thirdly, the pulse laser method is adopted to deposit an ultrathin LaNiO3 film on the obtained LaAlO3/SrTiO3. According to the method, an acid solution is firstly adopted to enable the SrTiO3 substrate to be treated to be in the step state with the specific width, the LaNiO3 film is deposited on the substrate, a layer of two-dimensional electron gas is formed on the interface, finally, the LaNiO3 film is deposited finally, the obtained film has the low resistance rate, meanwhile, the electrical transport property o can be regulated and controlled through control over the thickness of the LaAlO3, and optimization of the electrical transport property of the ultrathin lanthanum nickelate film is achieved. The preparing process is simple, the application range is wide, functionization is facilitated, and the wide application prospect is achieved.