The utility model discloses a negative pressure type flashback protection helmet for a hydrogen-oxygen welding cutter, and relates to the field of electromechanical equipment. The flashback protection helmet is mainly made from carbon fibers, and comprises a carbon fiber protection helmet housing structure, wherein a transparent eye and nose protection eyepiece is arranged on the front surface of the housing structure; the two sides of the transparent eye and nose protection eyepiece are fixedly arranged at two ears on the left and right sides of the protection helmet through buckles; ear hearing protection sound transmission holes are formed in the centers of fixed shafts at the two ears; an LED (Light-Emitting Diode) illumination lamp integrated onto the helmet is further arranged at the top of the protection helmet; continuous cambered cooling holes are formed from the rear parts of the two ears to the LED illumination lamp at the top; air vents are formed in the mouth part at the bottom of the protection helmet; a replaceable filter element screen is adhered to the inner sides of the air vents; protective cushions are further fixedly arranged at the cheeks of the protection helmet. According to the protection helmet with such a design, ergonomics and potential hazards in a welding cutting process are taken into account, the operation safety of an operator can be ensured, and a body is portable and comfortable.