This paper mainly discusses the tower models in lightning overvoltage calculation, especially analysis the lossless and lossy models. Build the muti-wave impedance model of the most commonly used towers, which are portal tower, glass tower, cat head tower and strain tower in accordance with the reality. The simulation shows that muti-wave impedance model has a higher lightning overvoltage than simple model under the same condition. This is because the simple model ignores the influence of resistance and inductance, so the more accurate the model is, the more effective the protection will be.