The invention relates to a method and device for measuring the flow speed of a dense paste based on electromagnetic signal cross correlation. The device comprises a test tube section, a primary instrument and a secondary instrument. When the dense paste flows through a field coil 1 or 2 during pipeline conveyance, a current carrier of the dense paste performs movements of cutting magnetic induction lines in an applied magnetic field, and an electromotive force vertical to the flowing direction of the dense paste is formed; electromotive force signals in the two field coils are guided out by an electrode to be acquired, processed and analyzed; and the delay time of the two field coils is calculated by a cross correlation analysis method of two measuring points, and the quotient of the separation distance and the delay time of the two field coils is the flow speed of the dense paste. The method and the device solve the difficult problem that a special measuring device and a special measuring method for measuring the flow speed of the dense paste on a project site are not provided, and a condition for monitoring the condition of the project site and accurately controlling the flow of the dense paste is provided.