This paper generalizes the traditional electromagnetic vector uniform array as an electromagnetic vector coprime array, and breaks the limit that the spacing between array elements is not more than half a wavelength. A direction of arrival (DOA) and polarization estimation algorithm is proposed for electromagnetic vector sensor coprime array via reduced-dimension Capon. The proposed algorithm does not need to assume that the polarization information is known, and only one-dimensional search is needed to avoid multi-dimensional search and enables automatic matching of DOA and polarization parameters. Compared with a uniform array with the same array element number, it significantly improves the angle estimates performance, and expands the antenna aperture. It also has a relatively high degree of freedom and lower complexity. Under the condition of same array and parameters, the angle estimation performance of the proposed algorithm is better than that of the ESPRIT algorithm and the trilinear decomposition algorithm.