Whole rumen content, fluid or solid fractions have been used often to assess the rumen microbial diversity and richness; however, the suitability of using each fraction assessing the ruminal microbial diversity and richness has not been evaluated. To compare the bacterial profiles in each fraction, samples of rumen content from 6 cows were collected via fistula and squeezed through 4 layers of cheesecloth to get liquid and solid fractions before analyzing with the next generation sequencing technique. Results showed that the Operational Taxonomic Units (OTUs) numbers (4897 ± 582, 5253 ± 855 and 4860 ± 615 for whole content, liquid and solid fraction, respectively) and Simpson indices (0.99 ± 0.008, 0.99 ± 0.006 and 0.99 ± 0.004 for whole content, liquid and solid fraction, respectively) among whole content, liquid and solid fractions were similar (P > 0.05). No statistical difference was found among the inner- or inter-group similarities for each kind of samples using Bray-Curtis metric (P > 0.05). At Phylum level, Bacteroidetes and Firmicutes were the predominant bacteria and accounted for more than 90% of the microbes in all samples in our study. However, richness of Bacteroidetes in liquid fraction was 64.29 ± 0.03% which was higher than that in solid fraction as 48.25 ± 0.04% (P < 0.05), while that of Firmicutes was 31.72 ± 0.03% in liquid fraction which was lower compared with that of solid fraction as 44.71 ± 0.05% (P < 0.05). At genus level, on analyzing the top 9 bacteria (accounting for more than 43% in quantity in all samples), the fold change values of liquid fraction versus whole content (liquid/whole) were 0.51, 0.73, 0.76, 0.82, 1.07, 1.19, 1.20, 1.35, and 1.38 for Coprococcus, Succiniclasticum, Butyrivibrio, Shuttleworthia, YRC22, Prevotella, Ruminococcus, CF231, and Oscillospira, respectively. These findings indicate that using whole, fluid, or solid fractions to assess the microbial diversity generate similar results. However, the richness of predominant bacteria in phylum and genus may differ depending on the sample fraction type.