Enabled by the widely existed distributed flexible alternating current transmission system devices in power systems, moving target defense (MTD) has been considered as an effective way to detect stealthy false data injection (FDI) attacks. However, due to the limitation of power system topology, not all stealthy FDI attacks can be detected in power system with MTD. In this article, the authors propose a joint meter coding (MC) and moving target defense (MC-MTD) method to cost-effectively improve the detection of stealthy FDI attacks through integrating MC with MTD. Detection conditions and requirements on MC-MTD are theoretically analyzed, which reveal the close coupling between MC and MTD in collaboratively detecting stealthy FDI attacks. The design of the coding matrix and the selection of encoded measurements are theoretically analyzed to integrate MC with MTD in a special case that the coding matrix is diagonal. An optimization of MC-MTD is formulated and approximately solved to improve detection effectiveness with a small defending cost. Finally, simulations are carried out on both direct and alternating current state estimations to validate the performance of MC-MTD.