Abstract: The 5th-Generation (5G) communication technology has brought new possibilities to the field of indoor positioning. Ultra-broadband (UWB) location technology, like 5G location, has the characteristics of large bandwidth and high frequency, but there are slight differences in positioning performance. To address the issues of poor accuracy and stability in single sensor positioning, a fusion positioning algorithm of 5G+UWB was studied in this paper. It establishes an indoor positioning system based on time difference of arrival (TDOA) for 5G, a UWB indoor positioning system based on trilateral positioning algorithm, and a 5G+UWB indoor positioning model based on the fusion positioning algorithm. The initial positioning results of each single system obtained through weighted least squares (WLS) algorithm are validated, followed by verification of improved positioning results obtained through Taylor series expansion method. Furthermore, experimental verification is conducted on the combined positioning results obtained by fusing the positioning results of the two single systems. It has been indicated by the experimental results that UWB single-system positioning shows lower accuracy but higher stability, while 5G single-system positioning exhibits higher accuracy but lower stability. After the combination of the two methods, the accuracy and stability of the combined system can be relatively high. The positioning accuracy of the combined system can be as high as 0.22 m and as low as 0.73 m, enabling sub-meter level positioning.