Herein,　a　series　of　TiO2/Bi0.5Na0.5TiO3　heterojunctions　with　different　mass　ratio　are　first　constructed　under　ultrasound　irradiation,　which　shows　superior　sonocatalytic　and　photoelectrochemical　properties.　The　im-proved　performance　is　attributed　to　the　internal　electric　field　and　close　interfacial　contact　of　TiO2　and　Bi0.5Na0.5TiO3,　which　promote　the　transfer　of　photoinduced　electrons　from　TiO2　to　Bi0.5Na0.5TiO3.　The　spontaneous　polarization　of　ferroelectrics　in　the　heterostructures　can　be　adjusted　by　ultrasonic　treatment　durations,　which　further　influences　the　internal　electric　field.　The　TiO2/Bi0.5Na0.5TiO3　sample　with　mass　ratios　of　5:1　and　ultrasonic　treatment　for　15　min　presents　the　highest　sonocatalytic　degradation　of　Rhodamine　B.　Moreover,　the　sonocatalytic　activity　also　shows　a　close　relevant　to　the　ultrasonic　temperature　and　frequency　of　degradation　process.　And,　the　(OH)-O-center　dot　radicals　are　mainly　responsible　for　Rhodamine　B　sonodegradation.　This　work　provides　a　novel　TiO2/Bi0.5Na0.5TiO3　heterojunctions　and　promotes　the　application　of　ferroelectrics　modified　materials　in　sono-/photo-catalysis.　(C)　2021　Elsevier　B.V.　All　rights　reserved.