Large long-wave antennas usually have several supporting towers. The supporting tower and ropes can affect the antenna radiation property .Traditional calculation method of long-wave antenna is analytic method, which has certain limitations such as being unable to calculate the effect of local structure changing on the electrical properties of the antenna. The FEKO software based on MOM is used to calculate long-wave antennas in this paper. The effect of supporting towers and ropes insulation on the electrical properties of long-wave antennas is analyzed. According to the calculation, it can be found that the supporting tower insulation can improve the resonance frequency and the effective height of the antenna, which provide the guidance in the long-wave antenna engineering.