The utero-placental-fetal circulation (UPFC) of 150 subjects during second and third trimester was examined by using color Doppler. Of them 89 were normal woman and 58 were patients with intrauterine growth retardation IUGR). Our results showed that UPFC was increased gradually during normal pregnant period. In IUGR patients it was revealed that TAV and Q of UmA, UmV and UtA decreased at 20th week of gestation, especially after 30th week. PI, RI and S/D ratio of UmA were increased, but TAV, Q of UmA and UmV were markly reduced, so was UtA. PI were increased, but the changes of RI, S/D ratio in UtA were not significant. Hemodynamical findings of UmA, UmV and UtA were abnormal in 92.53% of IUGR patients. Only 81.03% present abnormal S/D ratio of UmA (P < 0.01) and the difference was statistically significant. Maternal serum E3, HPL level in IUGR were significantly lower than that of the normal. 6KP level was reduced, TXB2/6KP ratio was significantly increased. TXB2/6KP ratio was markedly related with TAV, Q of UmA, UmV and UtA. Our results suggested that using color doppler ultrasound for examination of hemodynamical changes of UmA, UmV and UtA could revealed UPFC function directly. It is one of the best methods for monitoring IUGR and might be used for early diagnosis of IUGR. The main pathophysiological changes of IUGR were UPFC obstruction and placental disfunction.