In the narrow and elongated space of the coal mining face, Ultra-Wideband (UWB) base stations are distributed in a chain-like manner. Disturbances such as scattering, diffraction, and attenuation of communication signal transmission, along with the lack of a dynamic coordinate fusion mechanism among base stations, all reduce the positioning accuracy of the coal shearer. To improve the positioning accuracy of the coal shearer under UWB base stations on the working face, a coal shearer positioning method based on chain-style base station coordinate fusion is proposed. A coal shearer motion model adapting to the dynamic position changes of UWB base stations during the mining process was established. The Unscented Kalman Filter (UKF) was used to process the UWB measured deflection angle, and a chain-style base station coordinate fusion model based on the spatial distribution characteristics of UWB base stations was constructed to reduce the influence of time-varying disturbances. The gradient descent method was employed to iteratively optimize the position error between the coal shearer and the hydraulic support group, enhancing the coal shearer positioning accuracy in the absolute coordinate system. Furthermore, Kalman Filter (KF) was applied to filter the base station coordinate data to eliminate error accumulation caused by gradient descent, achieving high-precision positioning. Experimental results showed that within a ±40° range, the error of the UWB measured deflection angle after UKF processing was ±5°. Under conditions of antenna parallelism and non-parallelism between base stations, the Mean Squared Error (MSE) of the KF chain-style base station coordinate fusion method decreased by 91.3% and 95.8%, respectively, compared to traditional rigid coordinate fusion, and the Root Mean Squared Error (RMSE) decreased by 70.5% and 95.5%, respectively. Under conditions of no obstruction, partial obstruction, and full obstruction between base stations, the KF chain-style base station coordinate fusion method achieves higher positioning accuracy and stability for the coal shearer.