The invention discloses a mobile terminal and a harmful noise detecting method thereof and belongs to the field of terminals. The mobile terminal comprises a microphone, an audio signal detecting device and an audio processing device, wherein the audio signal detecting device is used for detecting the audio signal amplitude transmitted by the microphone, comparing the detected audio signal amplitude with a preset threshold value, and informing the audio processing device through an interrupt signal if the detected audio signal amplitude is larger than the preset threshold value, and the audio processing device acquires the audio signal amplitude from the audio signal detecting device, compares the acquired audio signal amplitude with a preset warning threshold value, and reminds a user if the acquired audio signal amplitude is larger than the preset warning threshold value. By the adoption of the mobile terminal and the method, environment harmful noise data can be detected conveniently and quickly in real time under the condition of low power consumption of the mobile terminal, battery energy is saved, human-machine interactive modes are rich, and diversified information transmission is realized.