Circulant Singular Spectrum Analysis (CiSSA) has good performance in the decomposition and extraction of periodic components of non-stationary signals. However, its decomposition of signals in complex environments suffers from spectral aliasing and difficulty in extracting feature information. Therefore, based on CiSSA, an improved circulant singular spectrum analysis and multi-point optimal minimum entropy deconvolution adjusted (ICiSSA-MOMEDA) is proposed and applied to the early faint fault diagnosis of axlebox bearings of urban rail train wheelsets. Firstly, the optimal embedding dimension is computed adaptively and accurately by an improved Cao's method. Then, the initial components obtained from the decomposition are reorganised by the K-ARs method. ICiSSA effectively solves the problems of spectrum confusion and fault information dispersion. Finally, ICiSSA is combined with MOMEDA to improve its ability to detect weak fault information. The superiority of ICiSSA-MOMEDA is verified based on the analysis of actual bearing data and comparison with other methods.