The invention discloses an in-vehicle network invasion detection method and 
system. The 
system comprises a timing module, a detection module, and a learning module; The timing module is used for transmitting the 
operation time of the 
system to the communication module, and the communication module records the 
timestamp of the receiving time of a received message and the identity 
label of a messagetransmitting node according to the 
operation time of the system. The communication module is used for transmitting the identity 
label and the 
timestamp of the receiving time to the learning module and the detection module. The learning module is used for determining a 
clock drift theoretical value of the transmitting node according to the 
timestamp of the receiving time when a network is normal,and carrying out the binding of the 
clock drift theoretical value with the identity 
label of the transmitting node. The detection module is used for determining the deviation of the 
clock drift of thetransmitting node relative to the 
clock drift theoretical value according to the timestamp of the receiving time during invasion detection. The system provided by the invention can be directly installed on a T-Box communication module, and the method and system are good in universality, and can guarantee the network safety of most vehicles.