CONTEXT:　Long-term　historical　information　on　national　-scale　grain　production　is　critical　for　ensuring　food　security　but　often　limited　by　the　lack　of　geospatial　data.　OBJECTIVE:　This　study　aims　to　conduct　the　first　systematic　investigation　of　grain　Cropping　Patterns　(CP)　in　China　over　the　past　two　decades,　shedding　light　on　the　roles　of　grain　expansion　and　intensification　in　sustainable　agriculture.　METHODS:　This　study　proposes　a　framework　to　fully　characterize　grain　production　patterns　considering　crop　types,　cropping　intensity　and　patterns　based　on　spatiotemporal　continuous　ChinaCP　datasets　(2005-2020).　Four　indicators　were　developed　for　measuring　the　Reality　to　Capability　Ratio　(RCR)　of　grain　production　regarding　the　total　yield　and　sow　area,　the　cropland　extent　and　cropping　intensity.　The　capability　of　grain　production　was　derived　based　on　grain　cultivation　history.　RESULTS　AND　CONCLUSION:　There　was　a　huge　gap　between　the　reality　and　capability　of　grain　production　in　China,　which　varied　with　grain　crop　types　and　cropping　patterns.　At　national　level,　a　vast　majority　(96%)　of　cropland　was　capable　of　grain　production,　and　two　fifths　of　cropland　quantified　for　double　grain　cropping.　However,　only　46.65%　and　24.89%　of　the　capability　was　implemented　for　grain　or　double　-grain　cropping　in　2020.　Maize,　rice,　and　wheat　was　ever　cultivated　in　76.88%,　57.05%,　and　25.18%　of　national　cropland,　respectively.　Winter　wheat　plays　an　important　role　in　stabilizing　grain　production　by　double　grain　cropping,　accounting　for　7/8　continuously　grain　-cultivated　areas.　However,　the　RCR　of　double　rice　was　only　7%　in　2020.　Bridging　these　gaps　could　potentially　triple　grain　production,　however,　achieving　this　increase　poses　challenges　due　to　a　series　of　constraints　related　to　cropland　fraction,　topographic　conditions　and　lack　of　agricultural　labors　along　with　rapid　urbanization.　This　study　found　that　there　was　a　continuous　Northeastward　movement　&　countryside　shift　in　grain　production.　Continuous　support　for　long-term　active　agricultural　systems　is　crucial　to　ensure　sustainable　grain　production　in　China,　with　a　special　emphasis　on　key　grain　productive　regions,　considering　targeted　cropping　patterns　and　regional　disparities.　SIGNIFICANCE:　This　study　enhances　our　understanding　of　grain　production　systems　in　China　based　on　long-term　cultivation　histories.　Findings　can　inform　the　development　of　more　geographic　-targeted　policies　concerning　grain　cropping　intensifications　to　ensure　food　security　and　environmental　sustainability　in　developing　countries.　The　long　term　spatiotemporal　continuous　CPChina　datasets　during　2005-2020　was　are　publicly　accessed　at:　https　://doi.org/10.6084/m9.figshare.25106948.