The utility model discloses a real time online malfunction alert based on voice frequency monitoring industrial equipment, and the malfunction alert comprises a microphone arranged on a monitored spot equipment area, an amplifier, an emitter, a receiver, a digital and analogue converter, a single chip computer and a light emitting diodes, wherein, the receiver, the digital and analogue converter, the single chip computer and the light emitting diodes are arranged in the monitoring room, and the microphone converts audio signals to electrical signals which are transferred to a voice frequency emitter after being amplified by the amplifier. The electromagnetic wave emitted by the voice frequency emitter is received by the receiver and then is changed into an analogue signal which is converted to a digital signal and is outputted to the single chip computer via the digital and analogue converter after the single chip computer processes the digital signal and obtains the voltage difference of the former unit time and the latter unit time. When the voltage difference value exceeds the threshold value generated when the equipment normally runs, the single clip computer outputs the high electrical frequency, and the light emitting diodes is conducted, thus the alert is realized when the spot area equipment runs whopping. The malfunction alert has the advantages of simple structure, intuitionistic display and convenient operation, and realizes the real time online monitoring of the voice frequency of the equipment running, synthetically reflects the exceptional situation of certain area equipment, and supervises and urges operators to find malfunction in time.