The invention provides a pulse state adjustable laser based on a three-dimensional Dirac semimetal saturable absorber. The pulse state adjustable laser comprises the three-dimensional Dirac semimetalsaturable absorber whose parameters can be actively regulated and controlled, a laser resonant cavity and a real-time feedback adjustment circuit module; in the laser resonant cavity, the three-dimensional Dirac semimetal saturable absorber whose parameters can be actively regulated and controlled directly determines the pulse characteristic output by the laser, the parameters of the saturable absorber are adjusted in real time with the assistance of the real-time feedback adjustment circuit module, it is ensured that the laser has excellent starting performance and pulse stability, the adjustment of the output pulse width of a mode-locked pulse is realized, and even flexible switching between the mode-locked pulse and a Q-switched pulse is realized; the three-dimensional Dirac semimetal saturable absorber whose parameters can be actively regulated and controlled has two modes of a reflection type and a transmission type; and self nonlinear parameters are adjusted in real time with assistance of the real-time feedback adjustment circuit module.