The invention discloses a user-defined protocol analysis device and 
system for 
USB (universal serial 
bus) communication and an operation method of the user-defined protocol analysis device and 
system. Effective user-defined protocol content is extracted from a universal 
bus protocol on a hardware level, and the user-defined protocol content is analyzed in combination with a decrypted user-defined protocol configuration file on a 
software level; the data 
encryption and decryption module encrypts data in an asymmetric 
encryption mode, the requirement for high 
confidentiality of a user-defined protocol is met, the 
wireless communication module remotely and wirelessly transmits a user-defined configuration file, and the user-defined protocol analysis 
system remotely sets and operates a mobile terminal on an 
engineering site. Meanwhile, the abnormal condition of the custom protocol content is detected in real time, so that when the custom protocol content is abnormal, the custom protocol content before the 
abnormality is transmitted back, and the 
abnormality of the custom protocol content within the preset time period before the 
abnormality is analyzed. The flexibility and accuracy of protocol analysis are greatly improved.