Smart grids occupy a central position in improving energy efficiency, ensuring stable grid operation and promoting the development of renewable energy, and their importance is self-evident. However, the data fusion process faces many challenges such as heterogeneous sources, uneven quality, complex algorithms, and difficulties in balancing real-time and accuracy, which restrict the full realization of the potential of the smart grid, and there is an urgent need to solve this problem through technological innovations and breakthroughs, so as to support the realization of a wider and more in-depth development of the smart grid. In this paper, we design a complete smart grid privacy-preserving data sharing scheme PB-TPR. The solution is based on Paillier encryption algorithm and BLS signature technology, which enables the control center to efficiently complete the aggregation processing of user power data and can ensure the privacy and security of user power data. Not only that, this paper uses threshold proxy re-encryption for secure data sharing and incorporates a strict authentication mechanism. Through security analysis, it has been demonstrated that the PB - TPR scheme exhibits superior efficiency compared to existing schemes during the privacy - preserving data sharing phase in smart grids.