The new safety valve muffler utilizes the noise-reduction principle of through-hole spray and impedance. It replaces the micro-porous piercing type with large-pore expansion and flow control, ensuring the smooth exhaust of the safety door in terms of structure. Multi-level perforation for sound absorption, combined with the impedance noise reduction principle, allows steam sound waves to enter the countless tiny holes of the porous sound-absorbing material, exciting molecular vibration of the porous material, transforming sound energy into heat energy to overcome frictional resistance and viscosity, thus achieving the ideal noise reduction effect and ensuring the smooth exhaust of steam.