A type of single-degree-of-freedom mechanical impact vibration system with dry friction and nonlinear constraints is studied. Through the fourth-order variable step Runge-Kutta numerical algorithm, the dynamics of the mechanical vibration system generated by the low-frequency excitation of the p/1 periodic motion are analyzed. The effect of system parameters on the dynamic characteristics of the vibration model is analyzed by the method of multi-parameter co-simulation, and the frequency hysteresis characteristics of Grazing bifurcation and Saddle-node in p/1 periodic motion are revealed. And the range of coexistence attractors. Finally, combined with the cell mapping method, the distribution of different attractors and attracting domains in the polymorphic coexistence area and their transition laws are studied. The research results show that the Grazing bifurcation with the decrease of the excitation frequency, the number of collisions of the p/1 periodic motion will gradually increase until the flutter motion occurs, and due to the irreversibility of adjacent periodic motion, changing different initial values in the hysteresis domain will result in different periodic motions coexisting.