Detailed　and　updated　maps　of　actively　cropped　fields　on　a　national　scale　are　vital　for　global　food　security.　Unfortunately,　this　information　is　not　provided　in　existing　land　cover　datasets,　especially　lacking　in　smallholder　farmer　systems.　Mapping　national-scale　cropped　fields　remains　challenging　due　to　the　spectral　confusion　with　abandoned　vegetated　land,　and　their　high　heterogeneity　over　large　areas.　This　study　proposed　a　large-area　mapping　framework　for　automatically　identifying　actively　cropped　fields　by　fusing　Vegetation-Soil-Pigment　indices　and　Synthetic-aperture　radar　(SAR)　time-series　images　(VSPS).　Three　temporal　indicators　were　proposed　and　highlighted　cropped　fields　by　consistently　higher　values　due　to　cropping　activities.　The　proposed　VSPS　algorithm　was　exploited　for　national-scale　mapping　in　China　without　regional　adjustments　using　Sentinel-2　and　Sentinel-1　images.　Agriculture　in　China　illustrated　great　heterogeneity　and　has　experienced　tremendous　changes　such　as　non-grain　orientation　and　cropland　abandonment.　Yet,　little　is　known　about　the　locations　and　extents　of　cropped　fields　cultivated　with　field　crops　on　a　national　scale.　Here,　we　produced　the　first　national-scale　20　m　updated　map　of　cropped　and　fallow/abandoned　land　in　China　and　found　that　77　%　of　national　cropland　(151.23　million　hectares)　was　actively　cropped　in　2020.　We　found　that　fallow/abandoned　cropland　in　mountainous　and　hilly　regions　were　far　more　than　we　expected,　which　was　significantly　underestimated　by　the　commonly　applied　VImax-based　approach　based　on　the　MODIS　images.　The　VSPS　method　illustrates　robust　generalization　capabilities,　which　obtained　an　overall　accuracy　of　94　%　based　on　4,934　widely　spread　reference　sites.　The　proposed　mapping　framework　is　capable　of　detecting　cropped　fields　with　a　full　consideration　of　a　high　diversity　of　cropping　systems　and　complexity　of　fallow/abandoned　cropland.　The　processing　codes　on　Google　Earth　Engine　were　provided　and　hoped　to　stimulate　operational　agricultural　mapping　on　cropped　fields　with　finer　resolution　from　the　national　to　the　global　scale.