Marine　algae　have　been　becoming　a　popular　research　topic　because　of　their　biological　implication.　The　algae　peptide-based　metal-chelating　complex　was　investigated　in　this　study.　Schizochytrium　sp.　protein　hydrolysate　(SPH)　possessing　high　Ca-binding　capacity　was　prepared　through　stepwise　enzymatic　hydrolysis　to　a　degree　of　hydrolysis　of　22.46%.　The　nanocomposites　of　SPH　chelated　with　calcium　ions　were　fabricated　in　aqueous　solution　at　pH　6　and　30　degrees　C　for　20　min,　with　the　ratio　of　SPH　to　calcium　3:1　(w/w).　The　size　distribution　showed　that　the　nanocomposite　had　compact　structure　with　a　radius　of　68.16　+/-　0.50　nm.　SPH　was　rich　in　acidic　amino　acids,　accounting　for　33.55%,　which　are　liable　to　bind　with　calcium　ions.　The　molecular　mass　distribution　demonstrated　that　the　molecular　mass　of　SPH　was　principally　concentrated　at　180-2000　Da.　UV　scanning　spectroscopy　and　Fourier　transform　infrared　spectroscopy　suggested　that　the　primary　sites　of　calcium-binding　corresponded　to　the　carboxyl　groups,　carbonyl　groups,　and　amino　groups　of　SPH.　The　results　of　fluorescent　spectroscopy,　size　distribution,　atomic　force　microscope,　and　H-1　nuclear　magnetic　resonance　spectroscopy　suggested　that　calcium　ions　chelated　with　SPH　would　cause　intramolecular　and　intermolecular　folding　and　aggregating.　The　SPH-calcium　chelate　exerted　remarkable　stability　and　absorbability　under　either　acidic　or　basic　conditions,　which　was　in　favor　of　calcium　absorption　in　the　gastrointestinal　tracts　of　humans.　The　investigation　suggests　that　SPH-calcium　chelate　has　the　potential　prospect　to　be　utilized　as　a　nutraceutical　supplement　to　improve　bone　health　in　the　human　body.