The invention provides a method for the preparation of super long fibrous titanium dioxide by taking cellulosic fibers as a template, relates to the method for the preparation of the super long fibrous titanium dioxide, and aims to solve the problems caused by the existing method that the prepared fibrous material cannot reach more than 15mu m in length; and the process is complicated, the sources are single, the cost is high and the yield is low. The method provided by the invention comprises the following steps: 1) preparing a natural fiber dispersion liquid; 2) preparing the dispersion liquid of natural fibers bonded with TiOH<3+>; 3) preparing the dispersion liquid of the natural fibers bonded with TiOSO4; 4) preparing the natural fibers bonded with titanium dioxide; 5) preparing natural wet fibers with core-shell structures bonded with the titanium dioxide; 6) preparing organic-titanium dioxide fibers with the core-shell structures; and 7) sintering at a high temperature and demolding the template. The method is applied to the fields of photoelectric materials, sensors, medicine release, energy storage materials, single molecule probes, neural signal detection and the like.