To improve the speed synchronization performance of dual permanent magnet synchronous motor (D-PMSM) considering parameter mismatches, a speed synchronization control strategy based on ultralocal model-free speed prediction control (UMFSPC) is proposed. Firstly, the mechanical motion equations of the D-PMSM system are established using the ultrarlocal model, so that the use of motor parameters is minimized. Concurrently, a full-order discrete disturbance observer is designed to estimate unmodelled components and disturbance elements within the ultralocal model and a method for controller parameter selection is proposed. Moreover, a cross-coupled structure is employed to compensate currents, enabling coordinated operation of the dual motors. Finally, simulation and experimental comparisons with conventional PI control are carried out. The results show that the proposed strategy effectively improve the synchronization performance caused by motor parameter variations.