Abstract: The invention provides a method and system for decoupling electric field of electrochemical model based on a parallel targeting method. The method includes selecting a negative or positive electrode region as a calculation region; selecting a solid or liquid phase current as an observed quantity, and a solid and liquid phase potential as a costate variable; inserting nodes between two endpoints of the calculation region, and determining a target value of the observed quantity of each node; constructing N calculation units; respectively performing a target shooting on the N calculation units; and determining whether a distance between the target shooting value of the observed quantity of the end point of each calculation unit and the target value of the observed quantity of the node corresponding to the end point of the calculation unit is within a preset range.