In this paper, we use DEA-Tobit model to conduct empirical study on the governmental supply efficiency of public service in Chongqing's 38 counties and the influencing factors during the period 2008-2011. The results show that the supply efficiency of basic public service at county level is generally low, and there is significant regional differences and strong volatility; per capita GDP, population density and population size, and level of education of the residents, are significantly correlated with the supply efficiency of basic public service at county level, but traffic density, urbanization level, and the proportion of government spending on public service to total fiscal expenditure, have no significant effects on the efficiency of basic public service at county level. Based on this, we propose some policy recommendations for enhancing the level of local economic development and the level of education, and reasonably guiding the residents' agglomeration.