Nanoparticles　with　unique　properties　have　potential　applications　in　food,　medicine,　pharmacology,　and　agriculture　industries.　Accordingly,　many　significant　researches　have　been　conducted　to　develop　novel　nanoparticles　using　chemical　and　biological　techniques.　This　review　focuses　on　the　synthesis　of　selenium　nanoparticles　(SeNPs)　using　polysaccharides　as　templates.　Various　instrumental　techniques　being　used　to　confirm　the　formation　of　polysaccharide-SeNPs　conjugates　and　characterize　the　properties　of　nanoparticles　are　also　introduced.　Finally,　the　biological　activities　of　the　synthesized　SeNPs　and　the　influence　of　structural　factors　of　polysaccharides　on　the　property　of　synthetic　nanocomposites　are　highlighted.　In　general,　the　polysaccharides　functionalized　SeNPs　can　be　easily　obtained　using　sodium　selenite　as　precursor　and　ascorbic　acid　as　reductant.　The　final　products　having　different　particle　size,　morphology,　and　selenium　content　exhibit　abundant　physiological　activities.　Structural　factors　of　polysacchairdes　involving　molecular　weights,　substitution　of　functional　groups,　and　chain　conformation　play　determinant　roles　on　the　properties　of　nanocomposites,　resulting　in　different　biological　performances.　The　review　on　the　achievements　and　current　status　of　polysaccharides　conjugated　SeNPs　provides　insights　into　this　exciting　research　topic　for　further　studies　in　the　future.　©　2020　Taylor　&　Francis　Group,　LLC.