A method for preparing organic thin-film transistor, comprising preparing a semiconductor layer between source and drain electrodes of the organic thin-film transistor using an axial-substituted phthalocyanine compound, wherein the centre ligand of said axial substituted phthalocyanine compound is an atom with 3 valences or higher, and the axial ligands are chlorine, fluorine, or oxygen which can be connected with the centre ligand of axial substituted phthalocyanine compounds;
- said axial substituted phthalocyanine compound is shown by the following formula:
- wherein, M represents the centre substituted ligand, and L, L′ represent the axial ligands.