Frequency selective metamaterial is an advanced material for manufacturing stealth airborne radomes. Its special structure probably makes traditional lightning protection measures fail. To identify suitable lightning protection measures for the metamaterial radome, the surface discharge behavior of the metamaterial during lightning strike needs to be studied. In this paper, a lightning strike simulation experimental platform was assembled to investigate surface discharge behaviors of circular split ring resonators (CSRR) metamaterial. A special combined discharge phenomenon was observed, which is considered to be the main reason behind the failure of the lightning protection of the metamaterial radome. Effects of lightning strike position, skin material, and number of lightning strikes on surface discharge characteristics of the metamaterial were studied carefully. Test results show that the lightning strike position has little influence on the surface discharge of the metamaterial, while the skin material and the number of lightning strikes have obvious effects on it. An equivalent chain circuit model was proposed to analyze surface discharge behavior, and a formula for estimating the surface discharge length of the skin was obtained. This work will help understand the lightning discharge phenomenon in metamaterials and provide theoretical guidance for lightning protection.