Peat soil is a type of soil within condition dominated by the litter of remaining plants which dead and rotten by nature so enrich with organic structure and water content in high concentration. This type of soil usually found in saturated water areas like swamp and basin. Called peat soil if organic structure content inside soil more than 30%, but swamp forests in Indonesia usually have more than 65% and more than 50cm depth. This research goal was to know the physical character (index properties) from peat soil and also the classification, to know the CBR (California Bearing Ratio) value of laboratory test and to know the CBR value after soaking the samples for 3 days. From this research it was found that peat soil from Pertanahan village, Sub-district Sei Kepayang Asahan Regency had 518.090% water content, 1.302 specific gravity, 3.672 void ratio, 0.454gr/cm3 moist unit weight, 0.098gr/cm3 dry unit weight, 45.032% ash content, 54.968% organic content, and it was classified as High Ash Peat. The peat soil had acidity pH of 4 and it was classified as Highly Acidic Peat with a pH less than 4.5. The CBR unsoaked value of peat soil was 6.750 % and the CBR soaked in three days was 2.800%.