A pin-on-disc system was established to study the generation mechanism and key impact factors of relationship between dynamic contact force and frictional squeal. Through the frictional squeal rig test, both intermittent and continuous squeals were produced repetitively. During the rig test frictional squeal, contact forces and acceleration of the pin end were sampled under various speed and loading force conditions, and the wavelet analysis, time-frequency analysis and feed-in energy calculation methods were used to investigate the relationship between dynamic contact force and frictional squeal. It was found that the frictional squeal would not appear unless the normal force was large enough, and the intermittent squeal would turn to continuous squeal with the quasi static part of normal force increasing to a limiting value, and vice versa. The mode coupling characteristic was discovered obviously when the frictional squeal appeared. Meanwhile the squeal frequency had a linear relationship with the quasi static part of normal force. There was also an apparent hysteresis effect between squeal frequency and the quasi static contact force. Energy feed-in is the precondition of squeal generation, and the variations of feed-in energy result in the fluctuation of amplitude envelope of the squeal sound pressure.