A juice extractor, wherein the juice extractor comprises a power assembly, a housing assembly, a snap-fitting assembly and a screw assembly; the power assembly comprises an electric motor, an electric-motor housing and a rotation shaft, and the electric motor drives the rotation shaft to rotate; the screw assembly is connected to the rotation shaft, and is provided inside the housing assembly; the snap-fitting assembly connects the housing assembly to the power assembly; and the housing assembly comprises a strainer assembly and a filtering-shield assembly, the strainer assembly is integrally formed by welding, the filtering-shield assembly is detachably fixed to and supported on the strainer assembly, and the filtering-shield assembly is provided with a filtered-juice separating slot that is capable of performing secondary filtration of an extracted juice, the juice extractor comprises a machine-body base, and the machine-body base comprises two front feet that protrude forwardly, wherein the screw assembly is a twin-screw assembly, wherein two screw rods are rotationally connected to the rotation shaft passing through a sealing connecter on the electric-motor housing and a transmission shaft on the sealing connecter respectively, and the twin-screw assembly is provided inside the strainer assembly, the twin-screw assembly comprises a crushing part and an extruding part, the crushing part is formed by engagement of threaded tooth cutters on outer circumferences of the screw rods, the extruding part is provided at a front end of the crushing part, a diameter of the extruding part is much less than a diameter of the crushing part, and a connection between the crushing part and the extruding part is provided with steps; and the extruding part is formed by a first thread part and a second thread part, the second thread part is provided at a front end of the first thread part, and a quantity of threads of the second thread part is greater than a quantity of threads of the first thread part, the strainer assembly comprises a crushing housing containing the crushing part of the twin-screw assembly, an extruding housing containing the extruding part of the twin-screw assembly, and a bellmouth part; and both of the crushing housing and the extruding housing are provided with a plurality of strainers or merely one or more extruding-housing notches are provided at a lower part of the extruding housing. the power assembly comprises an electric motor, an electric-motor housing and a rotation shaft, and the electric motor drives the rotation shaft to rotate; the screw assembly is connected to the rotation shaft, and is provided inside the housing assembly; the snap-fitting assembly connects the housing assembly to the power assembly; and the housing assembly comprises a strainer assembly and a filtering-shield assembly, the strainer assembly is integrally formed by welding, the filtering-shield assembly is detachably fixed to and supported on the strainer assembly, and the filtering-shield assembly is provided with a filtered-juice separating slot that is capable of performing secondary filtration of an extracted juice, the juice extractor comprises a machine-body base, and the machine-body base comprises two front feet that protrude forwardly, wherein the screw assembly is a twin-screw assembly, wherein two screw rods are rotationally connected to the rotation shaft passing through a sealing connecter on the electric-motor housing and a transmission shaft on the sealing connecter respectively, and the twin-screw assembly is provided inside the strainer assembly, the twin-screw assembly comprises a crushing part and an extruding part, the crushing part is formed by engagement of threaded tooth cutters on outer circumferences of the screw rods, the extruding part is provided at a front end of the crushing part, a diameter of the extruding part is much less than a diameter of the crushing part, and a connection between the crushing part and the extruding part is provided with steps; and the extruding part is formed by a first thread part and a second thread part, the second thread part is provided at a front end of the first thread part, and a quantity of threads of the second thread part is greater than a quantity of threads of the first thread part, the strainer assembly comprises a crushing housing containing the crushing part of the twin-screw assembly, an extruding housing containing the extruding part of the twin-screw assembly, and a bellmouth part; and both of the crushing housing and the extruding housing are provided with a plurality of strainers or merely one or more extruding-housing notches are provided at a lower part of the extruding housing.