A brake pedal simulator, a vehicle braking system and a vehicle are provided. The brake pedal simulator includes a brake pedal, a booster motor, an assembly portion, a first elastic member and a second elastic member arranged at axially spaced intervals on one side of the assembly portion, a rack and pinion mechanism positioned between the two elastic members, a thrust structure hinged to the brake pedal and capable of sequentially driving the first elastic member and the second elastic member to telescopically retract in the axial direction. The first elastic member provides a pedal preset force to the brake pedal, the output shaft of the booster motor is capable of cooperating with the second elastic member through the rack-and-pinion mechanism to provide assistance for the driving of the thrust structure, the first elastic member is compressed through the thrust mechanism in a first working state, and the first elastic member and the second elastic member are compressed synchronously through the cooperation of the thrust structure and the booster motor in a second working state. This provides a reliable braking feel of the brake pedal and simulates an accurate brake pedal force,and has the effects of good operation stability and corresponding quick brake pedal.