Farmland scale management can bring large scale benefits to producers, promote labour productivity and increase farmers' income. However, excessive concentration of farmland also has a few shortcomings, such as decreases in intensive farming, farmland productivity, and employment efficiency. Identifying the optimal land management scale is an effective means to improve agricultural production efficiency. Regression analysis is used to estimate the optimal land management scale under current productivity in China. Further, a decision graph has been drawn, which shows that the scale of big grain production households and comprehensive family farms is generally less than the optimal level, and an inverse relationship exists between farm size and productivity. Lastly, the suggestions that scattered land should be concentrated in the hands of big grain production households and family farms, and that land-lost farmers should work in their local agricultural industry, participating in the profit from land production are made.