Plastic products are very closely and widely used in our living such as food wrapping, garbage bags, vehicles, etc. Since this petrochemical polymer has durability, light weight, and its hydrophobic characteristic, it has been conventionally used. However, most of these products are hard to be degraded in nature and the retrieved piles of compost. Polylactic acid (PLA) has been widely used to produce biodegradable materials. This study was conducted to introduce the composition of the biodegradation test apparatus required for measuring the biodegradability of biodegradable polymers and the variety of methods of using the composting process. ISO 14855-1 (Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions – Method by analysis of evolved carbon dioxide – Part 1: General method) was borrowed to evaluate biodegradability. The PLA resin’s degradability in nature could be determined under composting condition before being produced. Based on weights between the initial and final samples, cellulose (positive control), TF, and XD had been degraded as 68.3, 54.0 and 44.0%, respectively. The other measurement showed 54.2, 51.3, and 41.8% of Cel, TF, and XD under CO₂ analysis of which lower the values might be caused by trouble shooting of gas collection and PLA resin (TF) was degraded as readily as cellulose. The trend of sample degradation was in order of “Cellulose>TF>XD”.