This　paper　proposes　a　modified　solar　assisted　ejector-compression　heat　pump　cycle　with　zeotropic　mixture　R290/R600a　(MHP)　for　water　heater　applications,　which　could　efficiently　utilize　both　the　air　source　energy　and　solar　energy.　Depending　on　the　solar　radiation　intensity,　MHP　contains　two　operation　modes,　i.e.,　Mode-A/-B　for　high/low　solar　radiation　intensity　conditions,　respectively.　In　MHP,　the　use　of　zeotropic　mixture　ensures　a　better　matching　characteristic　between　the　temperature　variations　of　the　refrigerant　and　water　in　the　condenser　due　to　its　temperature　glide　feature.　The　simulation　results　show　that　compared　with　the　conventional　heat　pump　cycle　(CHP),　as　the　condenser　inlet　saturated　temperature　ranges　45-80　degrees　C,　MHP-A　yields　28-33%　higher　COP　and　22-47%　higher　volumetric　heating　capacity　at　a　fixed　evaporator　outlet　temperature　of　10　degrees　C.　And　increasing　the　solar　radiation　intensity　is　beneficial　to　the　performance　improvement　of　MHP-A.　Additionally,　in　order　to　display　the　cycle　characteristic,　the　effects　of　other　critical　parameters　are　studied　in　detail,　including　the　evaporator　outlet　temperature,　mixture　composition,　heat　source　capacity　ratio,　etc.