The utility model relates to a device for jointly measuring polymer solution rheological property and core relative permeability efficiently and quickly. The device comprises a polymer injection unit, an oil injection unit, an on-line rheometer, a core holder, an oil separator, a pressure difference transducer, and an electronic weighing machine which are connected through a pipeline and a control valve, wherein the two ends of both the on-line rheometer and the core holder are connected in parallel to the pressure difference transducer respectively; and the polymer injection unit is connected in parallel with the oil injection unit and then connected with the on-line rheometer, the core holder, the oil separator, and the electronic weighing machine sequentially. The utility model has the advantages that rheological property measurement can simulate oil pool seepage environment more truly, so as to get the rheological property of a polymer solution system; the calibre of a capillary tube on-line rheometer is optional to meet different demands; and the joint measurement on the rheological property and the relative permeability of the polymer solution system can be performed, and the rheological property can be measured in an on-line real time manner.