<p>This paper discusses the feasibility and necessity of utilizing joint inversion of 2.5-D controlled source frequency-domain electromagnetic (CSEM) and surface-to-borehole electromagnetic (SBEM) methods in mineral exploration. The 2.5-D CSEM method has been widely applied in mineral exploration; however, it currently rarely provides detailed discrimination of ore body. To conduct this research, we developed a domain decomposition based volume integral equation (DDVIE) algorithm with a digital linear filtering transform solver for forward modeling. The regularization inversion algorithm employs contrast source inversion (CSI) to optimize the parameter functions with the observed data term and the contrast source term in both primary and secondary fields. An inversion procedure for 2.5-D CSEM and SBEM data, based on an iterative volume integral solver with domain decomposition, has been evaluated for the solution of large-scale and complex inverse problems. Joint inversion is compared with traditional single 2.5D CSEM inversion through inversion experiments on a mineralized structure and two metal deposits in China. The results indicate that a combination of well-designed electromagnetic measurements and modern 2.5D inversion can provide detailed discrimination of geoelectric structures and vein bodies.</p>