To improve the work of emergency care and early cardio-pulmonary-brin resuscitation in our county, which is characteristic of abruptness and contingency, a new type of ventilator is highly required. It is hoped that such a ventilafor has a simple safe valve and does not need electric current from the mains. Also, the ventilator should be small in size, light in weight, simple in operation, easy to carry, swift to assembly, and reliable in ventilation. With the principle of pneumatic logic elements and the design of the integration of pneumatic circuits, we have successfully developed the Emergency Micro-ventilator, which accords with the above requirements. It has been confirmed that the ventilator is very effectual and reliable in ventilation support for the patients(n = 55) under general anesthesia without any case of hypoxemia, hypercapnia, hypotension, arrhythmia and so on, and the mechanical performances are stable.