Abstarct: Constructed wetlands are among the green technologies to purify contaminated waters and compared to conventional wastewater treatment systems, they are more cost-effective and have more simplicity. However, these systems have some limitations such as; high occupancy levels, limitation on providing oxygen, inability on sufficient nitrogen removal and application limits for strong wastewater treatment. In this study, a pilot was designed to treat the landfill leachate in a subsurface flow constructed wetland. This study and the tests were done in the period of 60-day after plants growth in three different systems including: Control Constructed Wetland containing the main leachate (without Vetiver plant species), Main Constructed Wetland containing the main leachate (with Vetiver plant species) and Constructed Wetland with a 10-percent diluted leachate (with Vetiver plant species). Constructed wetlands were designed with the dimension of 1.5m*0.5m*0.5m. The bed of this constructed wetland was filled with gravel, sand, and rock with the effective porosity of 35,48 and 25 percent. Vetiver plant species used in this case study were planted to 16 per square meters in both the main and diluted constructed wetland. Sampling and measurement was conducted each 5 days due to the 5-day hydraulic retention time. baxsed on the results of this study, removal efficiencies obtained for diluted and undiluted leachate were: BOD5, 79% and 29%; COD, 54 and 33%; TSS, 57 and 39%; Ammonium, 73 and 25%; Nickel 46 and 35% respectively. Due to the results of this research in each phase removal efficiency of assessed parameters were relatively high. Among pollution indexes the highest amount was for ammonia and BOD5, respectively.