The invention discloses a monitoring and management system for combustible gas in a cable well. The system comprises measurement modules, a data transmission module, a master station center and an alarm module. At least two measurement modules are arranged and include gas sensors and power supplies, wherein the gas sensors and the power supplies are connected mutually. The data transmission moduleacquires gas concentration values uploaded by the gas sensors and the electric energy of the power supplies in real time by connecting lines and transmits the obtained concentration values to the master station center by means of wireless data transmission; the master station center and the alarm module are connected; and the alarm module is an acousto-optic alarm device. According to the invention, with the multiple measurement modules and the data transmission module, large-scale and point-to-point monitoring of flammable gas concentration values in cable wells is realized by controllingby the master station center; and the system has functions of data storage and real-time alarming. Therefore, the safety of the operation and maintenance personnel and system facilities is improved and the stability and reliability of the power grid operation are improved.