The invention relates to a remote monitoring and early warning system and method for fire extinguishing agent stock in fire fighting trucks. The monitoring system comprises pressure sensors, data collection modules, a network transmission module, a display screen and an alarm device. The pressure sensors are installed in fire extinguishing agent storage tanks of the fire fighting trucks, the data collection modules are connected with the pressure sensors through data lines and used for collecting pressure signals output by the pressure sensors, the network transmission module is in wireless connection with the data collection modules and transmits the pressure signals collected by the data collection modules to a fire fighting monitoring host in a wireless mode, the display screen is connected with the fire fighting monitoring host and used for displaying the fire extinguishing agent stock information of each fire fighting truck according to output signals of the fighting monitoring host, and the alarm device is used for giving an alarm to remind workers to add fire extinguishing agent when the fire extinguishing agent stock of one fire fighting truck is lower than a preset threshold value. The current fire extinguishing agent stock in the fire fighting trucks can be detected, and the fire fighting trucks are allocated by a control platform according to the current fire extinguishing agent stock in the fire fighting trucks to carry out fire fighting operation more effectively.