To address the issue of insufficient exhaust energy at low engine speeds in opposed-piston two-stroke（OP2S）engines, research on an electrically-assisted boosting system was conducted to enhance the boosting capability. A 1D simulation model for an electrically assisted turbocharged OP2S engine was established, and the in-cylinder energy and exhaust energy utilization efficiencies of pre-installed, mid-installed, and rear-installed electrically assisted turbocharging modes were analyzed. The results indicate that the exhaust energy is insufficient for the turbocharger to operate stably at low engine speed under 2 300 r/min. The electrically assisted turbocharging can extend the stable operating speed range of the OP2S engine. In addition, the increase of the exhaust energy at low engine speed makes the exhaust gas turbocharger which could not operate stably also have a supercharging effect, further increasing the pressure ratio. It suggests a synergistic effect between the two systems. The mid-installed mode exhibits the highest in-cylinder energy utilization efficiency, surpassing the lowest（the pre-installed mode）by 1.1 percentage points without compromising exhaust energy utilization.