A novel design and implementation method of all digital phase-locked loop (DPLL) for carrier synchronization of digital coherent demodulation in SSB Direct-sequence spread spectrum communication system is proposed. The full digital phase-locked loop Phase detector and numerical controlled oscillator are implemented in vector mode and rotation mode of the algorithm respectively, and an appropriate compromise is made between the number of iterations and the complexity of the algorithm. According to the characteristics of the proposed multi-step correlation algorithm, the distribution pattern of pilot frequency and data composition is optimized. The simulation results show that, taking a system where 6 users share 4 resource blocks as an example, the carrier synchronization scheme based on optimized frame structure can achieve higher estimation accuracy and better bit error performance with less pilot overhead compared to using classical frame structure.