To　investigate　the　protein–starch　interactions　in　myofibrillar　protein　gels　under　the　ultrasonic　pretreatment,　the　effect　of　cassava　starch　content　and　ultrasonic　pretreatment　on　gelling　properties　of　myofibrillar　protein　from　Lateolabrax　japonicus　was　studied.　For　the　myofibrillar　protein–starch　(MPS)　solutions,　the　turbidity　and　elastic　modulus　increased　when　the　starch　content　increased　from　0%　to　8%.　For　the　MPS　gels,　the　hardness,　chewiness,　gumminess,　and　water　holding　capacity　increased　with　the　starch　content,　whereas　the　cooking　loss　and　whiteness　decreased.　Starch　incorporation　promoted　the　conversion　of　free　water　to　immobilized　water　and　bound　water.　The　active　sulfhydryl　content　decreased　with　the　starch　content,　whereas　the　hydrogen　bond　and　hydrophobic　interaction　content　increased.　Fine　network　structure　containing　pores　at　uniform　size　was　formed　in　the　MPS　gel　at　an　increased　starch　content,　as　shown　in　the　scanning　electron　microscope　images.　When　the　ultrasonic　pretreatment　was　introduced,　the　elastic　modulus　of　MPS　solutions　and　hardness,　chewiness,　gumminess,　hydrophobic　interaction,　β-sheet　content,　and　microstructural　compactness　of　the　MPS　gels　increased,　whereas　the　turbidity　of　the　MPS　solutions　and　cooking　loss,　whiteness,　free　water　content,　active　sulfhydryl　content,　and　random　coil　content　of　the　MPS　gels　decreased.　The　MPS　gel　containing　8%　of　starch　and　subjected　to　ultrasonic　pretreatment　showed　the　highest　hardness,　chewiness,　and　gumminess　of　220,　150,　and　160 g,　while　the　lowest　cooking　loss　of　2.5%　among　all　samples.　Therefore,　the　gelling　properties　of　myofibrillar　protein　from　L.　japonicus　could　be　enhanced　by　the　starch　incorporation,　ultrasonic　pretreatment,　and　their　synergistic　effect.　©　2023　The　Authors.　Food　Frontiers　published　by　John　Wiley　&　Sons　Australia,　Ltd　and　Nanchang　University,　Northwest　University,　Jiangsu　University,　Zhejiang　University,　Fujian　Agriculture　and　Forestry　University.