Improving medium-low yielded farmland is one of the most important ways to realize total arable land equilibrium and protect food security of china. In this study, we use the national agricultural sub-county data and the second national soil survey data to investigate the type, spatial-temporal distribution characteristics and yield potential of medium-low yielded farmland in china. The results showed that the farmland quality had increased gradually from 1985 to 2008. Low-yield farmland’ proportion had decreased form 50.01% to 28.61%; the proportion of medium-yield farmland’s had increased from 24.86% to 37.91%; high-yield farmland’ proportion had increased from 25.13% to 33.48%. The main distribution areas of medium-low yielded farmland are northeast china, north china and the Lower-middle Reaches of Yangtze River. The main types are barren land, arid land, sloping land, water logging paddy land, water logging dry land, saline-alkali land, Aeolian sandy land and so on. We also calculated the production potential and proposed the technical countermeasures, future research direction and policy recommendations to improve the medium-low yielded farmland.