PM2.5　and　other　fine　particles　are　one　of　the　indoor　air　pollutants　that　pose　a　great　threat　to　human　health.　Long-term　exposure　to　dust　will　cause　heart　and　lung　diseases　and　even　cancer.　A　large　number　of　high-energy　electrons　and　active　particles　in　low-temperature　plasma　can　directly　act　on　harmful　substances　in　the　air,　which　has　high　potential　in　purifying　PM2.5.　In　order　to　achieve　high　purification　efficiency　of　PM2.5,　multi-needle　electrode　was　used　to　generate　large　area　plasma　through　negative　DC　corona　discharge,　and　the　purification　characteristics　of　PM2.5　were　investigated.　It　is　found　that　increasing　the　number　of　electrode　needles　can　improve　the　purification　efficiency　of　PM2.5　under　different　applied　voltages,　but　saturation　effect　may　exist.　The　electrode　humidity　will　affect　the　efficiency　of　PM2.5,　and　the　efficiency　in　wet　state　is　slightly　higher　than　that　in　dry　state.　©　2022　IEEE.