Earthquakes often cause severe disasters. Taiwan is located in an earthquake zone, where earthquakes occur frequently. For example, the Meinong earthquake in Kaohsiung in 2016 and the Hualien earthquake in 2018 caused the collapse of buildings in Tainan and Hualien, resulting in a total of 232 deaths and more than 100 injuries. Due to the strong vibration, earthquakes are often accompanied by fire and the leakage of toxic gases, causing loss of life and property. In this study, we integrate Arduino, sensors, and transmission technology to design an earthquake detection and warning system. When an earthquake is detected, the system immediately notifies everyone to evacuate. When the harmful gas concentration exceeds a critical value, the warning light is switched on, and the exhaust fan is turned on to extract the indoor toxic gas. When the flame sensor detects a flame, the system activates an alarm to warn people to escape quickly. In the designed system, capacitive three-axis accelerators are used as vibration measurement sensors to issue warnings in the early stage of an earthquake. In addition, the system includes an IR flame sensor to detect fires and an MQ series air quality sensor to detect harmful gases. The newly designed sensing system not only has the advantage of notifying people immediately during an earthquake but is also cheap and easy to use.