In　the　food　industry,　there　has　been　a　debate　about　the　interactions　between　fish　gelatin　and　polysaccharide　with　the　interaction　mechanism　in　different　solute　and　solvent　systems　still　unclear.　This　article　tries　to　explore　interactions　between　fish　gelatin　(FG)　and　Tremella　polysaccharides　(AP)　by　the　turbidity　titration.　Especially,　the　turbidity　was　greatly　influenced　by　pH,　polymer　ratio,　total　polymer　concentration,　and　ionic　strength.　Optimally,　the　most　complex　coacervates　could　be　electrostatically　formed　at　a　mass　ratio　of　1:1　and　pH　4.0,　which　was　collected　for　subsequent　characterization.　In　addition,　there　was　a　positive　correlation　between　the　turbidity　and　the　total　concentration,　while　the　ionic　strength　was　just　reverse.　Modern　instruments　including　FTIR,　XRD,　DSC,　SEM　and　rotational　rheometer　were　adopted　to　characterize　the　complex　coacervates　formed　at　different　pH.　Results　showed　that　the　FG–AP　complex　coacervates　showed　porous　network　structure　and　had　the　strongest　apparent　viscosity　with　viscoelastic　modulus　at　pH　3.5.　These　results　suggested　important　implications　in　how　we　make　a　good　alternative　for　fat　in　food　dairy.　©　2022　Elsevier　Ltd