Objective  To examine the need and related family, community and society factors of frailty-related daily life and mental care among oldest-old people and to provide evidences for taking supportive measures.

  Methods  We recruited 3 448 home-living residents aged ≥ 75 years with stratified random cluster sampling from communities covered by 10 community health care centers in Tangshan city; then we conducted a household questionnaire survey among the participants between July 2016 and January 2017 with Comprehensive Frailty Assessment Instrument (CFAI), Activities of Daily Living (ADL), and University of California, Los Angeles (UCLA) Loneliness Scale.

  Results  Various degrees of frailty were identified among all the participants; 23.32 % (804/3 448) and 68.9 % (2 377/3 448) of the participants reported strong demands for daily life care and spiritual comfort and most of the demanders considered children and spouse as the providers for the two types of care. Multivariate analyses showed that significant impact factors for daily life care included frailty degree (t = 21.876), age (t = 11.673), and helps from siblings (t = 2.676), neighbours (t = 3.871), children (3.812), spouse (t = – 2.806), volunteers (t = – 2.735) and other family members(t = – 2.573) among the home-living oldest-old people (P < 0.05 for all); while those for spiritual comfort were frailty degree (26.572) and helps from neighbours (t = 13.060), children (t = – 6.995), spouse (t = – 4.607), neighborhood committee (t = 2.729), siblings (t = – 2.165), and education level (t = – 3.057) (all P < 0.05).

  Conclusion  Family function, community and social support are the basis of daily life and mental care for oldest-old people; we should strengthen the construction of support system and improve the level of overall care for the oldest-old people.