The invention discloses an automatic unsealing system on an automatic electric energy meter detection line. The automatic unsealing system comprises an unsealed electric energy meter, a control center, an unsealing device, and an automatic assembly line. The unsealing device comprises a PC, a PLC, a machine vision apparatus, and an unsealing mechanical apparatus. The PC communicates with the PLC, the machine vision apparatus, and the unsealing mechanical apparatus. The unsealed electric energy meter is arranged on the automatic assembly line. The PLC is connected with the automatic assembly line. The invention also discloses an automatic unsealing method on the automatic electric energy meter detection line. Manual intervention is not required in a whole electric energy meter unsealing process. The automatic unsealing system automatically detects whether the PLC is at the ready, automatically moves the unsealed electric energy meter, automatically detects the unsealed electric energy meter, automatically unseals the unsealed electric energy meter, automatically notifies the PLC of unsealing accomplishment, increases the efficiency of the whole unsealing process, shortens unsealing time, and reduces the labor cost of enterprises.