The invention relates to a polyaniline derivative, a preparation method of reductive poly Schiff base of the polyaniline derivative and application of the polyaniline derivative, in particular relates to a polyaniline material as well as a preparation method and application thereof, and is mainly used for solving the technical problems that the existing polyaniline has poor dissolubility in an organic solvent and is difficultly processed into a film. The structure formula of the polyaniline derivative is shown in the specification. The preparation method of the polyaniline derivative comprises the following steps: adding conjugated poly Schiff base, a solvent and sodium borohydride in a three-neck flask, heating to 10-70 DEG C, and stirring and refluxing for 10-72 hours; cooling, pouring a product obtained from the former step into methanol; and filtering and drying to obtain the polyaniline derivative. The polyaniline derivative can be used as photoelectric materials including an electrochromic material, a fluorescent sense material, an acidic sense material, a cavity transmission material, a three-order non-linear material, an anti-counterfeiting material, a camouflage material and an automobile rearview mirror material, and can also be used for proton detection.