The invention discloses a hand-held chemical oxygen breathing device for self-rescue in emergency, comprising an one-way breathing valve A (4), an one-way breathing valve B (5), an one-way breathing valve C (8), filter sieve plates (9), an air regeneration agent (10), a breathing bag A (12), a breathing bag B (11) and pressure relief valves (15), and further comprising a breathing mask (1), a mixed flow buffer tank (13), a handle (14), and an air regeneration tank (7). With simple use, the device can effectively reduce breathing backpressure and enhance the consistency of regenerated air components entering the breathing bags to improve the breath quality and comfort of users.