A switchable water-saving valve, comprising: a water inlet insert, including a housing and a water inlet portion, wherein the housing has a ring-shaped body with external threads, the water inlet portion is fixedly arranged in the housing and has at least one water inlet and at least one water outlet (126; 126A), and the at least one water inlet is in fluid communication with the at least one water outlet (126; 126A); a flow channel insert (20; 20A; 20B), having an annular body and fixedly arranged in the housing in flow direction below the water inlet portion, wherein a plurality of guide holes is arranged circumferentially around the flow channel insert at intervals and extends through the flow channel insert, the guide holes in fluid communication with the water outlet; a switch holder (30; 30A; 30B), having an annular body and rotatably positioned in flow direction below the flow channel insert, wherein the switch holder (30; 30A; 30B) has a top surface and a bottom surface, and a plurality of first water flow holes and a plurality of second water flow holes are arranged circumferentially around the top surface at intervals and extend through the top surface; an aerator holder (40; 40A; 40B), having an annular body and fixedly arranged in flow direction below the switch holder (30; 30A; 30B) 1, wherein the aerator holder (40; 40A; 40B) is positioned in the switch holder (30; 30A; 30B) and forms a gap between the aerator holder (40; 40A; 40B) and the switch holder (30; 30A; 30B), and a grid of water outlet holes is formed in the bottom surface of the aerator holder, the water outlet holes in fluid communication with the first water flow holes, wherein when the switch holder (30; 30A; 30B) rotates to a first position where the plurality of first water flow holes is aligned with the plurality of guide holes respectively, water flowing into the plurality of guide holes flows through the first water flow holes and out of the plurality of water outlet holes, and when the switch holder (30; 30A; 30B) rotate to a second position where the plurality of second water flow holes is aligned with the plurality of guide holes respectively, water flowing into the plurality of guide holes flows out of the plurality of second water flow holes. a water inlet insert, including a housing and a water inlet portion, wherein the housing has a ring-shaped body with external threads, the water inlet portion is fixedly arranged in the housing and has at least one water inlet and at least one water outlet (126; 126A), and the at least one water inlet is in fluid communication with the at least one water outlet (126; 126A); a flow channel insert (20; 20A; 20B), having an annular body and fixedly arranged in the housing in flow direction below the water inlet portion, wherein a plurality of guide holes is arranged circumferentially around the flow channel insert at intervals and extends through the flow channel insert, the guide holes in fluid communication with the water outlet; a switch holder (30; 30A; 30B), having an annular body and rotatably positioned in flow direction below the flow channel insert, wherein the switch holder (30; 30A; 30B) has a top surface and a bottom surface, and a plurality of first water flow holes and a plurality of second water flow holes are arranged circumferentially around the top surface at intervals and extend through the top surface; an aerator holder (40; 40A; 40B), having an annular body and fixedly arranged in flow direction below the switch holder (30; 30A; 30B) 1, wherein the aerator holder (40; 40A; 40B) is positioned in the switch holder (30; 30A; 30B) and forms a gap between the aerator holder (40; 40A; 40B) and the switch holder (30; 30A; 30B), and a grid of water outlet holes is formed in the bottom surface of the aerator holder, the water outlet holes in fluid communication with the first water flow holes, wherein when the switch holder (30; 30A; 30B) rotates to a first position where the plurality of first water flow holes is aligned with the plurality of guide holes respectively, water flowing into the plurality of guide holes flows through the first water flow holes and out of the plurality of water outlet holes, and when the switch holder (30; 30A; 30B) rotate to a second position where the plurality of second water flow holes is aligned with the plurality of guide holes respectively, water flowing into the plurality of guide holes flows out of the plurality of second water flow holes.