Multi Soil Layering (MSL) is a method of wastewater treatment (contaminated water) organic by utilizing soil as a main medium and organic material formed in the form of beams bricks and arranged in layers among zeolite layer. MSL reactor made of acrylic box 50 cm (L) x15 cm (H) x 50 cm (W) cm contains the beam brick 4 cm (H) x9 cm (L) x15 cm (W) cm with mixture as volcanic soil, actif charcoal, bagasse and iron powder (7,5: 1: 1: 0,5) and a permiable layer used zeolite (2-3 mm). The sample is peat water located in the Perawang area, Siak District, Riau Province of Indonesia.The Research was done by flowrate variation of 5, 10, 20 and 40 mL. min-1 in aeration and nonaerasi conditions. From the research that the efficiency MSLmethod in peat water treatment at a flow rate of 5 mL. min-1 is better,itcould remove of Color, COD, BOD, Organic content are 93,57%; 90,48%; 93,65%; 91,07% on aeration condition and 92,86%; 89,52%; 92,06%; 89,05% on nonaerasi, while for pH could changed from 4,26 to 6,93 for aeration condition and from 4,26 to 6,91 for nonaeration. This results showed that the MSL method is an efficient way of peat water treatment to be fresh water. The flow rate and aeration-nonaeration conditions are key factors in increasingthe effectiveness of the MSL method.