Compared with other lightning targets on the ground, the most notable feature of a wind turbine is that the blades are usually in a rotating state when lightning strikes. To study the mechanism of blade rotation influencing wind turbine on triggering lightning, lightning discharge comparison tests based on a typical 2-MW 1:30-scaled wind turbine model with an arching high-voltage electrode were conducted under different modes of stationary and rotating blades. Negative polarity switching impulses of 250/2500 μs were applied to the arching electrode. The up-and-down method was adopted for 50% discharge voltage and the discharge process was observed. The experimental results showed that under the condition of a 4 m gap, the breakdown voltage decreases and the connection point of the leaders approaches the high-voltage electrode with increasing blade speed, indicating that the wind turbine’s blade rotation enhances the triggering of lightning. The analysis showed that the blade rotation could be altering the charge distribution on the blade tip, resulting in varied ascending leader development on the blade tip, which affected the discharge development process.