This paper studies the spatial differences of grain production efficiencies in China using a panel data set on 30 provinces (cities) for the period 1987-92. A stochastic frontier production function is estimated to derive the technical efficiencies across the regions. The results suggest that technical inefficiencies are significant with remarkable provincial and zonal differentials. The marginal productivities of factors and their convergence (divergence) over time, the decomposition of total factor productivity, and the effects of major determinants on technical inefficiencies are also studied in detail.