Wind turbines often suffer from lightning strikes, iceing and other disasters. The installation of an electrothermal ice-melting device on the blade can effectively remove icing, but it will increase the risk of lightning strikes on the blade. In order to study the change of lighting attachment manner and the reliability of the existing standard lightning protection device after the blade is retrofitted with ice-melting device. This paper designs a 1:30 scaled-down rotatable 3WM ice-melting wind turbine blade for long gap lightning discharge test. Comparing the interception efficiency of the lightning receptors before and after the installation of the ice-melting device on the blade, the results show that when the lightning leader develops on the windward side of the blade, the ice-melting blade has the phenomenon of lightning receptor failure, lightning strike at the junction of the ice-melting device and the blade body. In the most serious case, the protection efficiency of the lightning receptor is only 55%. The ice-melting device ‘ shields ’ some of the lightning receptor, and the charge around the blade is distributed in an arc shape after the blade rotates, so that the ice-melting device is broken down at a lower voltage. Through the lightning strike probability model of ice-melting blade, it is found that there is a great risk of lightning at the junction of ice-melting device and blade body. The results reveal the lightning attachment manner of the ice-melting blade and further guide its lightning protection design.