Recently, the modular multilevel converters (MMC) has been widely used in high voltage direct current (HVDC) transmission systems due to its advantages of low cost, low loss and low total harmonic distortion. But in the large-scale MMC valve, a large amount of switching noise will cause a complex and harsh electromagnetic interference (EMI) environment inside its valve towers, which will interfere with the normal operation of the electronic system. This paper proposes a novel copper layer based EMI coupling model as a precondition for near-field radiation EMS research on electronic system in MMC-HVDC system. Taking driver PCB as example, the concept of interference weight coefficient is proposed and the value of EMI current, which will interfere switches operation or even destroy the drive IC, can be calculated. The effectiveness of the novel coupling model is proved by comparing the calculated value of interference current with the simulation result.