Traditional field oriented control method requires multiple phase current sensors and position sensors, leading to high system costs, large size, and reduced reliability. To address this issue, a sensorless control strategy for permanent magnet synchronous motor (PMSM) based on single DC bus current sampling was proposed. To solve the problem of current reconstruction blind zones in conventional single DC bus sampling schemes, a vector phase-shifted method was introduced. Additionally, a high-frequency square-wave injection control strategy was proposed to tackle the sensorless control challenges of PMSM at low speeds. Finally, a simulation model was built on the Matlab/Simulink platform to verify the theoretical analysis. The simulation results showed that the proposed strategy effectively solved the blind zone problem in the low modulation ratio region and sector boundaries, enabling sensorless low-speed operation of the PMSM.