The invention discloses a vehicle-mounted terminal communication method applied to 
engineering machinery vehicle networking. The vehicle-mounted terminal communication method includes a method for 
internet access communication between a vehicle-mounted 
terminal unit and a remote 
server unit based on 
wireless second-generation or third-generation communication and a method for communication between the vehicle-mounted 
terminal unit and a 
local function unit. The method for communication between the vehicle-mounted 
terminal unit and the 
local function unit includes: a method for communication between the vehicle-mounted terminal unit and a detecting and maintaining computer unit; a method for communication among the vehicle-mounted terminal unit, an engine 
electric control unit and a vehicle 
electric control unit which are based on CAN (
control area network); a method for communication between the vehicle-mounted terminal unit and a geographical position information detecting unit based on RS232 (recommend standard 232); a method for communication between the vehicle-mounted terminal unit and a vehicle 
body balance-degree or gradient detecting unit based on RS485; and a method for communication among the vehicle-mounted terminal unit and human-interactive input and output units. The vehicle-mounted terminal achieved by the methods can be applied to various 
engineering applied vehicles, transmission and management of vehicle state data can be realized, requirements and functions of a vehicle networking 
system can be met, and conditions for sharing and serving 
engineering vehicle data are provided.