The invention discloses a portable mining safety monitoring device, comprising a microcontroller module, a power module, a reset module, a data storage chip, a wireless communication circuit, a supersonic detector, and a data acquisition module. The input end of the microcontroller module is connected with a compactness detection circuit and a key setting circuit. The output end of the microcontroller module is connected with a liquid crystal display circuit, a buzzer warning circuit, and a LED drive circuit. The output end of the LED drive circuit is connected with a LED lighting circuit. The data acquisition module comprises a methane gas sensor, a signal conditioning circuit, and an A/D conversion circuit. The output end of the A/D conversion circuit is connected with the input end of the microcontroller module. The power module comprises a power supply and a power switch. The device is novel in design and simple in structure, and has functions of detecting harmful gas concentration of a mine in real time and acquiring surrounding coal seam compactness. The device is simple in operation and good in practicality, and is safe and reliable.