The invention discloses a monitoring method and a monitoring structure for the deflection of a bituminous concrete core wall. Anchor plates (2) are respectively arranged from the outside to the inside of the bituminous concrete core wall (1) at two sides of the upstream and the downstream (at the same elevation) of the bituminous concrete core wall (1); a strain displacement meter (3) is arranged between every two adjacent anchor plates (2) in the vertical direction; so that the deflection deformation of the core wall can be conjectured by monitoring the deformation of the core wall under the action of the self gravity and outer force through the strain displacement meters; and instruments are distributed along different heights, so that the whole deflection deformation situation of the core wall can be obtained. As the above technical scheme is adopted, compared with the conventional monitoring method and the conventional monitoring structure, for the monitoring method and the monitoring structure disclosed by the invention, the construction cost is relatively lower, the construction is convenient, the civil construction progress cannot be influenced, coherent construction grinding weak surfaces cannot be generated, and the instruments can be adaptive to worse work environments, and also can be adaptive to lager deformation of the core wall.