Abstract: The paper aims to study the potential productivity and the main limiting climatic factors of grain crops in eastern agricultural region of Qinghai, based on the daily meteorological elements and actual grain yield data of 13 meteorological stations from April to September during 1987-2017 in eastern agricultural region of Qinghai, we analyzed the spatio-temporal variation characteristics of the potential productivity, actual yields and the yield gaps of grain crops by using a successive correction model. The results showed that: the photosynthetic potential productivity (PPP) decreased during 1987-2017 and photo-thermal potential productivity (PTPP), climate potential productivity (CPP) and actual grain yield increased since 1987; the PTPP had achieved 37% of the PPP and the CPP had achieved 53% of the PTPP which indicated that the potential productivity had a great promotion space, and the temperature and precipitation were the limiting climatic factors to improve the potential productivity; the yield gap between the CPP and actual productivity decreased with a rate of 178.6 kg/hm2 every 10 years, the further improvement of the actual yield was more difficult in Guide, Xunhua and Tongren, but the actual yield gaps could be reduced by optimizing fertilization and rationally utilizing heat resources for most other areas.