One, the advance warning signal: sound 36 seconds, stop 24 seconds, 3 times for a cycle (time 3 minutes). Pre-alarm sounding, the public should immediately stop all work, people should close the doors and windows, cut off the power supply, extinguish the stove fire, turn off the gas, liquefied petroleum gas, etc., carrying valid documents, essential supplies and personal protective equipment, rapid evacuation and orderly to the nearby underground air-raid shelters, air-raid works, air-raid shelters or designated sheltered areas.

Two, the air raid alarm signal: sound 6 seconds, stop 6 seconds, 15 times for a cycle (time 3 minutes). Air raid alarm sounded when the enemy aircraft or other air raid weapon has been approaching in the city's airspace, air raid action is about to or has begun to cast, notify people to quickly evacuate, shelter and other protective measures. Can not enter the underground air defense shelters, human defense works, air raid shelters and other hidden territory, the public should immediately use the terrain and features near the shelter, lying on the ground with their hands on their heads to prevent air attacks.

Three, the release of the alarm signal: sound a long tone, 3 minutes of continuous sound for a cycle (time 3 minutes). Release the alarm sounded when the air raid or war temporarily relieved, the public should be organized, orderly return to their homes or work, while you can resume normal production and life in the city. If there is an air raid caused by the collapse of houses, fires and casualties, etc., should be in their units or communities under the unified organization, and actively carry out self-rescue, mutual rescue, firefighting, repair and other actions.

Many cities conduct air-raid siren tests on a certain day of the year, usually for 15 minutes, in accordance with the order of the pre-alarm, air-raid siren and deactivation siren, which is announced in the news media before the test, so as not to cause panic in the community. Air defense alarm test is to mourn the people killed by the air raid, two is to test the integrity of the human defense equipment and coverage, three is to carry out national defense education, enhance the general public's concept of national defense, improve the ability to cope with war and natural disasters and self-rescue and mutual aid.