Centenarians are the fastest growing population worldwide. However, this group has been less studied in developing countries. Contemporary centenarians in China have experienced many ups and downs due to historical reasons, which may have resulted in a population with different characteristics from those in other countries. This study aimed to investigate the current sociodemographic characteristics, health profiles, and social relationships of Chinese centenarians. We conducted face-to-face surveys in April 2017 with centenarian residents in Suixi County, the first "International Healthy Longevity Area" in China. A total of 100 centenarians were involved, including 67 females and 33 males. Information for socioeconomic and demographics characteristics, quality of life (physical, cognitive, and psychological function), and social support and relationships was collected. Sex differences in each measure were examined. We find that good self-reported health, good life satisfaction, intact memory function, independence, and unsatisfied healthcare needs were reported by 24.4%, 45.9%, 31.6%, 46.3%, and 33.4% of the respondents respectively. Subjective symptoms among males were less prevalent (p < 0.05). There were no statistical significant sex differences in cognitive and psychological function. The major source of care provision has been family. Generally, the centenarians had intimate relationships within families but maintained distant relationships with friends and communities. Our results bring attention to family-based care to provide informal care, and health education to promote healthy behaviors and healthcare utilization, for the oldest-old in China. The findings also imply a crucial role of good relationships with family in exceptional longevity.