The invention relates to a pressure-controllable respirator, and belongs to the technical field of coal mine and fire rescue and escape. The problems that in the prior art, a respirator is large in size, inconvenient to carry and use and high in breathing temperature, the product effectiveness cannot be judged, and an oxygen generation agent is wasted are solved. The pressure-controllable respirator comprises a mouth and nose mask, a breathing pipe, an oxygen generating part, an air bag (4), an upper cover (5) and a pressure relief device (7), wherein the oxygen generating part comprises an oxygen generating tank (31), a three-way unit (32) and an initial oxygen generating device (33); and one end of the breathing pipe (2) is connected with the mouth and nose mask (1), the other end of thebreathing pipe (2) is connected with the oxygen generating tank (31), the air bag (4) is connected with the oxygen generating tank (31), and the upper cover (5) covers the oxygen generating part (3).According to the respirator, by arranging the pressure relief device, the internal pressure of the air bag is adjusted, the three-way unit divides oxygen, and the interior of the oxygen generating tank is visual and capable of dissipating heat, so that the effects of saving the oxygen generation agent, reducing the weight and size, reducing the oxygen generation temperature and being convenient to use and carry and high in safety are achieved.