Background: With the rapid spread of COVID-19 worldwide, the clinical practice in cancer treatment of complementary and alternative medicine (CAM) becomes significantly different. This study was designed to explore the changes of China’s cancer patients’ perception, attitude and clinical practice in CAM after the pandemic of COVID-19. Methods: A multicenter before-after cross-sectional study was conducted, including 448 cancer patients by a survey. Results: For perception, half of the cancer patients (51.2%) reported they had received adequate information in CAM cancer treatment and had a great expectation in medical appointment pattern (40.2%). For attitudes, most of the cancer patients (79.4%) had full of confidence in CAM cancer treatment and showed a strong desire to learn more about CAM (70.2%). Nearly half of the cancer patients (44.0%) presented their oncology clinics had been greatly affected by COVID-19, however, most (82.8%) refused to the online medical service pattern. For clinical practice, Chinese herbal medicine was widely used before (89.5%) / after (90.3%) the epidemic of COVID-19 and the main purpose of receiving CAM therapy was to improve immune system (71.8%). The frequency of patients’ visiting the clinic decreased significantly (P < 0.001), and most (90.0%) didn’t change their follow-up pattern. The majority of the cancer patients (83.3%) were identified as CAM users and the only predictive factor was national health insurance in the multivariable logistic regression model. Conclusion: China’s cancer patients show more interest and confidence in treating cancer by CAM, and the new medical pattern such as medical appointment, has been gradually accepted during the COVID-19 pandemic. However, the cancer patients’ perception in CAM and online medical service pattern still need to be improved.