The invention provides an OBDII 
code reading card device and a 
system and method for upgrading the OBDII 
code reading card device. The device comprises a master control MCU, a data storage module, a display key module, a diagnosis interface module and a 
power management module, wherein the data storage module, the display key module, the diagnosis interface module and the 
power management module are connected with the master control MCU respectively. The master control MCU comprises an application function module and an 
upgrade module, wherein the 
upgrade module comprises an 
upgrade interface module and is used for providing interfaces for upgrading codes and data for the outside and providing interfaces for upgrading the data and the codes for the inside, and the application function module is used for achieving the diagnosis application function of an OBDII 
code reading card. By carrying out safety 
verification on a file to be upgraded, unlimited times of upgrade of the OBDII code 
reading card is achieved, timely upgrade of the product is guaranteed, the problem of abnormal upgrade caused by equipment exception, misoperation of a user and the like is also prevented, malicious 
cracking and interference of a 
third party on the upgrade process can be effectively prevented, and therefore the safety and security of the product are guaranteed.