The objective of this study was to evaluate the feasibility of the determination of neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents in feed using polyester mesh bag. Four different methods, including national standard method, polyester mesh bag method, Ankom fiber analyzer method and polyester mesh bag instrument method, were utilized to determine the contents of NDF and ADF contents from 17 different feeds, respectively, and a comprehensive comparison was conducted to evaluate the differentiation of the results among the different methods. The results showed as follows: 1) there were no significant differences in the contents of ADF and NDF in feeds that determined by the four methods (P>0.05). 2) The content of NDF determined by the polyester mesh bag method was similar to that determined by the national standard method, and the determination results of the two methods exhibited a strong positive correlation: y=0.998 3x+0.130 5(x was the content of NDF determined by the national standard method, and y was the content of NDF determined by the polyester mesh bag method), n=17, r=0.999 7, P<0.01. 3) The content of ADF determined by the polyester mesh bag method was similar to that determined by national standard method, and the determination results of the two methods presented a strong positive correlation: y=0.999 0x-0.034 0 (x was the content of ADF determined by the national standard method, and y was the content of ADF determined by the polyester mesh bag method), n=17, r=0.999 9, P<0.01. In conclusion, the polyester mesh bag method for determining the contents of NDF and ADF contents in feed has some advantages such as shorter analysis time, higher efficiency, lower cost, and improved precision, thus it can replace the national standard method. In addition, the Ankom F57 filter-bag can be replaced by polyester mesh bag when using the Ankom fiber analyzer to determine the contents of NDF and ADF contents in feed.