The invention relates to a ball grinding mill load detecting device, in particular to an intelligent grinding sound frequency spectrum analyzer. The intelligent grinding sound frequency spectrum analyzer is characterized in that ball grinding mill sound frequency signals acquired by a sensor (1) enter a signal amplification unit (3), controlled by a CPU (central processing unit) (6), to be subjected to automatic gain regulation via a signal isolation unit (2), then enter a bandpass scanning unit (4) and an A/D (analog/digital) sampling unit (7), which are controlled by the CPU (6), to be subjected to refined frequency band acquisition and analysis and operation processing, and finally, are converted into standard signals to be outputted by a 4-20mA unit (10). The CPU (6) controls a communication unit (9) and a human-computer interaction unit (8) simultaneously. The intelligent grinding sound frequency spectrum analyzer has the advantages of high anti-interference capability, high accuracy, simplicity in operation and use, low cost and the like, and is particularly suitable for ball grinding mill load detection in severe environments of concentration plants.