The present invention relates to the technical field for the determination of calcium carbonate content, and discloses a method and an apparatus for rapidly determining the calcium carbonate content in paper, and applications of the method. The apparatus comprises a first reaction container, a second reaction container, a solution adding device arranged on the upper portion of the first reaction container, a first gas conducting pipe, a second gas conducting pipe, a gas pump and a conductivity detection device. According to the present invention, a phase transfer reaction method is used, wherein a strong acid solution reacts with quantitative calcium carbonate in a closed system to produce carbon dioxide, the carbon dioxide is absorbed by a strongly alkali solution to generate sodium carbonate, and by determining the change of the conductivity of the strongly alkali solution along with the time and calculating through a standard curve, the calcium carbonate content in the paper is rapidly determinate; and the operation is simple, the calcium carbonate content in the paper can be accurately determined by determining the conductivity with the simple device and by using the formula calculation, and the accuracy and the precision of the detection result are high.