In order to detect circles quickly and accurately with less memory,we present a fast circle detection method based on particle sw arm optimization (PSO) in this paper.Under some optimization strategies with each particle as a candidate circle,the appro ach uses some operations for updating the particles to complete the circle detec tion.The optimization strategies in this approach use an image blocking to limit the circle detection area of interest,and the size of each image block depende on the result of generating particles.In order to redu ce the generation probability of those useless particles and improve the efficiency of detection,we use an image pyrami d and the evidence-based method to verify the effectiveness of particles.Experi mental results validate that the proposed method is suitable for detecting circles which are regular,hand-drawn,nested,incomplete or containi ng a lot of noise.The proposed method can exclude much interference in a short time,and accurately detect circles.It exhibits small memory consumption,fast running speed and wide application range.