The electro-mechanical brake (EMB) system, as a true form of drive-by-wire braking, has become a primary research focus for next-generation electric vehicle (EV) braking systems due to its compact structure, fast braking response, and high modularity. The quality of EMB configuration and matching design directly affects vehicle braking performance. This study investigates the EMB composed of the electro-mechanical joint module (EMJM) and the ball screw. It proposes an integrated design methodology based on multi-objective optimization, taking into account the functional requirements, key component parameter constraints, and design objectives of the EMB. First, the design requirements for the EMB are determined based on its dynamic characteristics and functions. Then, constraints on the ball screw’ load, diameter, lead, and the EMJM's speed and torque are considered, along with spatial constraints, to establish a feasible solution set. Finally, a multi-objective optimization function is created to minimize system mass, reduce braking response time, and minimize continuous stable braking torque for the optimal EMB configuration.