The　wide　applications　of　natural　starches　in　industries　often　encounter　problems　such　as　easy　syneresis,　pH　sensitivity,　and　heating　instability.　The　influences　of　an　addition　of　10%　(w/w)　jicama　non-starch　poly-saccharides　(PEP-3P　&　PEP-6P)　with　different　molecular　structures　on　the　multiscale　structure,　gelatinization　properties,　and　in　vitro　digestibility　of　gelatinized　oat　starch　(OS)　were　investigated.　Compared　to　OS,　the　swelling　power,　solubility,　short-range　ordered　structure,　crystalline　shape,　and　apparent　viscosities　did　not　show　significant　differences.　The　contents　of　amylose　leaching,　proportions　of　amorphous　area,　thermal　resistance,　and　gel　strength　increased　to　some　extents,　but　contents　of　rapidly　digestible　starch　(RDS)　decreased　after　PEPs　were　added.　Moreover,　PEP-3P　and　PEP-6P　with　different　chemical　components　and　molecular　weights　performed　differently　in　two　main　aspects.　Firstly,　the　swelling　power　and　solubility　were　markedly　different　between　OS/　PEP-3P　and　OS/PEP-6P.　Secondly,　the　in　vitro　digestible　behaviours　of　OS/PEPs　showed　different　patterns　as　the　contents　of　RDS,　slowly　digestible　starch　(SDS),　and　resistant　starch　(RS)　were　different.　Based　on　the　above　results,　the　inhibition　effects　on　digestibility　of　PEPs　were　probably　attributed　to　the　enhancement　of　starch　gels　during　and　after　gelatinization.　Molecular　structures　of　PEPs　did　affect　the　functional　properties　when　PEPs　were　combined　with　OS.　These　findings　may　provide　more　fundamental　information　about　interactions　between　non-starch　polysaccharides　and　starch.