Tumors are a major disease that seriously threaten the life and health of Chinese residents. Existing tumor diagnosis methods heavily rely on the subjective experience of doctors and include many issues, such as prolonged diagnosis, severe trauma, and high misdiagnosis rate. Therefore, it is crucial to develop a tumor diagnosis technology with intelligent properties to improve the level of diagnosing tumors in China. Raman spectroscopy is a label-free optical technique used for diagnosing benign and malignant tumors, classifying tumor subtypes, pathological diagnosis of biopsy, and in situ near-real-time imaging. Moreover, Raman spectroscopy combined with artificial intelligence has led to an intelligent diagnostic method. In this paper, the research progress of Raman spectroscopy for diagnosing various tumor types over the past three years was reviewed. Furthermore, three main aspects of the conventional Raman spectrum, Raman imaging, and probe diagnoses combined with the spectrum were introduced, and the prospect of Raman spectroscopy in the diagnosis of tumors in the future was discussed.