A microfluidic chip, a liquid sample detection device and a liquid sample detection method are provided. The microfluidic chip includes: a liquid inlet; a waste tank; an accommodating chamber respectively communicated with the liquid inlet and the waste tank at two ends of the accommodating chamber; and at least one giant magnetoresistance structure attached to a wall of the accommodating chamber and having a marker attached thereto. The giant magnetoresistance structure is configured to be attached with magnetic bead particles combined with a to-be-detected object in a liquid sample through a combination of the to-be-detected object and the marker.