A dual-motor hybrid power system for a vehicle, the dual-motor hybrid power system comprising a single synchronizer, wherein the dual-motor hybrid power system further comprises: a first motor; a second motor; a first driving shaft configured to be turned by the first motor; a second driving shaft configured to be turned by the second motor and disposed to be coaxial with the first driving shaft, the single synchronizer being disposed around the second driving shaft between the first motor and the second motor; an engine disposed to be coupled with the second driving shaft via a clutch; an intermediate shaft disposed to be parallel with the first driving shaft and the second driving shaft; a first gear set (7, 14) disposed between the first driving shaft and the intermediate shaft and having a first speed-reducing ratio, wherein the first driving shaft is continuously coupled with the intermediate shaft via the first gear set (7, 14); a second gear set (12, 15) having a second speed-reducing ratio; a differential driven by the intermediate shaft; and a first sleeve coupled to the first driving shaft, wherein the synchronizer is configured to be switched between a neutral position, a first-speed-ratio position, and a second-speed-ratio position, wherein in the neutral position, the second driving shaft is decoupled from the first gear set (7, 14) and the second gear set (12, 15), wherein, in the first-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the first gear set (7, 14), and wherein, in the second-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the second gear set (12, 15). a first motor; a second motor; a first driving shaft configured to be turned by the first motor; a second driving shaft configured to be turned by the second motor and disposed to be coaxial with the first driving shaft, the single synchronizer being disposed around the second driving shaft between the first motor and the second motor; an engine disposed to be coupled with the second driving shaft via a clutch; an intermediate shaft disposed to be parallel with the first driving shaft and the second driving shaft; a first gear set (7, 14) disposed between the first driving shaft and the intermediate shaft and having a first speed-reducing ratio, wherein the first driving shaft is continuously coupled with the intermediate shaft via the first gear set (7, 14); a second gear set (12, 15) having a second speed-reducing ratio; a differential driven by the intermediate shaft; and a first sleeve coupled to the first driving shaft, wherein the synchronizer is configured to be switched between a neutral position, a first-speed-ratio position, and a second-speed-ratio position, wherein in the neutral position, the second driving shaft is decoupled from the first gear set (7, 14) and the second gear set (12, 15), wherein, in the first-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the first gear set (7, 14), and wherein, in the second-speed-ratio position, the synchronizer couples the second driving shaft with the intermediate shaft via the second gear set (12, 15).