The utility model discloses a measuring and calculating device of fluctuation of molten aluminum in an aluminum electrolysis cell. The device comprises a signal acquiring module (6), a data transmission module (3), a data conversion module (4) and an embedded controller (5), the signal acquiring module (6) is used for acquiring voltage signals of equidistant predetermined points on a large bus of the aluminum electrolysis cell, the data transmission module (3) is used for transmitting the signals acquired by the signal acquiring module (6), the data conversion module (4) converts the voltage signals into high-speed serial data, the embedded controller (5) processes the serial data, the signal acquiring module (6) is installed on the bus of the aluminum electrolysis cell, and the signal acquiring module (6), the data transmission module (3), the data conversion module (4) and the embedded controller (5) are sequentially communicated. According to the measuring and calculating device of fluctuation of the molten aluminum in the aluminum electrolysis cell, real-time and reliable data can be guaranteed when equidistant voltage values of a positive pole of the aluminum electrolysis cell are measured.