The phenomenon of self-synchronization in mechanical systems is used to describe the realization of synchronous of two or more rotors which are fixed on a rigid base that are elastically connected to the ground. Such phenomenon can be observed when the two motors are rotating with the driven of separate exciters under the influence of each other, if certain conditions are met. In previous researches, cases when using DC motors instead of AC motors are rarely studied and the parameters are normally simplified in these limited studies. In the presented work, the synchronization phenomenon of a dual-rotor system driven by two DC motors was researched by simulation. In the simulation, the Lagrange equation was used to establish the motion equation of the mechanical system, and the influence of the electromagnetic torque of the motors on the mechanical system was quantified and being merged in the system equations. Worth mentioning, the influence of the motor inductance, which is usually ignored for simplification, was considered when the motor equation was established. Additionally, this phenomenon was verified in experiments of an accordingly designed system with the help of visual-based measurement techniques.