Abstract: The speed of the tailings dam has a significant impact on the safe operation of the tailings dam. In order to explore the maximum safe up-dam speed of a new tailings pond. The finite element fluid-solid coupling method is used to analyze the safety impact mechanism of different up-dam speeds on the tailings dam, and to determine a reasonable speed of the up-dam. The research shows that with the increase of up-dam speed, the growth rate of effective stress between tailings particles becomes slower, the growth rate of pore water pressure becomes steeper, the uplift wetting line is buried deeper, and the sliding force increases. At the same time, the consolidation degree is reduced, the mechanical strength of the tailings is reduced, and the anti-sliding force is reduced, thereby reducing the stability of the tailings dam. The maximum safe dam speed of a new tailings pond is determined to be 15m/a based on the comprehensive anti-sliding stability coefficient, the minimum wetting line depth and the degree of consolidation. The upper dam velocity increases with the increase of elastic modulus, permeability coefficient, cohesion and internal friction angle. It decreases with the increase of the height of the accumulation dam. With the dry density and stacking dam slope ratio, it first increases and then decreases, showing a parabolic relationship, and there is a maximum value of the stacking dam rate.