In order to study the DNA content and the cell cycle of different tissues of fish, as well as enrich the material which was used to determine the genome size of fish in vivo, Pseudorasbora parva was used as experimental material, and flow cytometry was used to determine the DNA content and analyse the cell cycle in different tissues. The results showed that there were some differences in DNA contents in blood, muscle, fin, gill, liver, kidney and gonad of Pseudorasbora parva, and the highest and lowest tissue of DNA contents was the muscle and kidney, gill, which reached 3.20×10-6 μg and 3.05×10-6 μg, respectively. DNA contents in fin were similar to that in blood, so the fin could be as a material to determine the genome size of Pseudorasbora parva in vivo. All tissues of Pseudorasbora parva shown the cell cycle, the ratio of the time phase of G0/G1 in gonad and liver was the lowest, and the two tissues shown higher cell proliferation index that was 17.81% and 13.19%, respectively, while the gill was detected the lowest cell proliferation index which was merely 6.54%, there were also differences about the time phase of cell cycle in different tissues.