The leaching rule of heavy metals in coal gangue was studied by 240 h sequential cyclic leaching experiments which were carried out in a new dynamic cyclic radial flow leaching device. CPAM was added to the leaching solution to investigate the sedimentation characteristics of the solid particles. Results showed that, Na in coal gangue was dissolved in the water and formed alkaline solution when the time of leaching reaction extended, leading to a higher pH at the beginning of the reaction. The concentration of As and Zn ions was increasing during the first 24h of leaching but decreased from the 24^th to 72^nd hours. The concentration of Cr, Pb and Ba was all increasing during the first 120h. The leaching rate of Cr irons increased by the alkalinity of the leaching solution from the 120^th hour to the 240^th, but the concentration decreased as the times of sample test increased. Pb ions were oxidized into smaller solubility of precipitation in the process of leaching, which decreased the migration ability of Pb ions to the leaching solution. The concentration of Ba irons in the leaching solution decreased as the solution diluted and sediments of Ba irons formed. During the period from the 120^th hour to the 240^th, the organics in the solution were decomposed by microorganism, and water was added. Therefore, the concentration of COD and BOD was diluted. In the first 24h, the values of TON and NH₃-N had a wave type change, both of which increased after 24h. The sedimentation rate of the solid particles in the leaching solution slowed down as the leaching time extended, and prolonged the sedimentation duration. Some nitrogen compounds in coal gangue were dissolved in water, and ionization of ammonium ions in the leaching solution formed the alkaline environment.