By advance of miniaturization of electronic devices, a ground of a printed circuit board is tend to be small and complicated and the ground may have some defects, such as connectors or clearance halls of vias. In this paper, we analyze the coupling between a microstrip line and a slot in a ground on a PCB using the MTL method to examine an effect of the signal integrity for the slot in the ground. And also we analyze emission from a PCB with slot using coupling slot voltages which is calculated by the MTL method. To calculate by using the MTL method, per-unit-length parameters, such as the self or mutual capacitances and inductances, of a microstrip line and a slot are calculated using the FDTD method. Finally, we show the validity of the method in this paper, comparing results using the MTL method with numerical results using the FDTD method. It is shown that the proposed method is validated by comparing results by the MTL method with results by the FDTD.