Graphite production was achieved unexpectedly in the course of demonstrating a new ultrasonic-assisted wheat straw pulping method at room temperature and at atmospheric pressure. The graphite material was found in the ultrasonic-assisted pulp (UP) ash, as shown by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and TEM analysis. UP ash contained both inorganic and organic components. The total content of inorganic components in the ash was 81.9%, while the content of organic component (graphite material) was 18.1%. The graphite content in the pulp was calculated to be approximately 4.5%. This work describes a new meaningful approach for the facile preparation of graphite materials. The graphitization was based on the ultrasonic cavitation mechanism of extreme condition, while the process would be divided into three steps, degradation of lignin, graphene formation, and graphitization process.