The invention provides a transmission strategy and bandwidth selection method and system for multicast service of a power wireless private network, and the method comprises the steps: S1, calculatingthe signal-to-interference-and-noise ratios of all user terminals of a current cell in an SFN transmission mode, and generating a sorting list; S2, changing the user terminal with the highest sequenceinto a PTP mode, and calculating the single-frequency network spectral efficiency of the current cell; S3, recalculating the signal-to-interference-plus-noise ratio of each user terminal, updating the sorting list, and returning to the step S2; S4, obtaining the number of the user terminals of which the current cell is changed into the PTP mode corresponding to the maximum value of the spectral efficiency of the single frequency network and a sorting list; and S5, determining the number of the user terminals in the SFN mode in the current cell and the SFN bandwidth. According to the invention, the hybrid transmission of PTP and SFN is realized, the influence of worst user signal quality on resource allocation in an SFN transmission mode is reduced, the resource demand of multicast serviceis further reduced, the wireless resource utilization rate of a power wireless private network is improved, and the occurrence of network congestion is reduced.