With rapid economic growth and urbanization, there has been an increasing debate on food security and crop supplies in China. Grains have become central to China's agriculture policy of ensuring food security mostly through domestic supply. Accurate production statistics are essential for research, monitoring, and planning. Recent increases in crop production reported by national statistics have come under increasing scrutiny. This paper provides an approach to validate Chinese official grain data, based on integrated socioecological indicators of terrestrial net primary production. This approach, grounded on agriculture's biophysical spatially explicit constraints, provides a powerful means to check the plausibility of China's grain production statistics at different administrative levels, generates insights about their discrepancies, and can contribute to improved crop production measurements.