Abstract: Objective To investigate the influence of social support on the incidence of mild cognitive impairment (MCI) and its subtypes among the elderly in communities of Guiyang city.Methods A total of 2 159 persons aged 60 years or older with normal cognitive function were followed-up and surveyed with questionnaires and scales in Guiyang city.The study analyzed the influence of social support on the incidence of MCI and its subtypes by Cox regression model.Results Objective support was a protective factor for MCI(relative riskRR=0.424,95% confidence intervalCI:0.220-0.819) and amnestic MCI(RR=0.366,95% CI:0.174-0.767).With economic support source≥2,the incidence of amnestic MCI(icidence densityID=12.29/1 000 person years) was higher than that of nonamnestic MCI (ID=3.35/1 000 person years).Economic support from the spouse reduced the risk of amnestic MCI's incidence(RR=0.253,95% CI:0.106-0.601).Other social support had no influence on the incidence of MCI subtypes(P> 0.05).Conclusion The results suggest that social support is helpful to decrease MCI incidence.The determinants of nonamnestic MCI are different from tha of MCI and amnestic MCI.It is necessary to study the feature of MCI subtypes for developing preventive strategies.