Objective　To evaluate the correlation between the sound pressure and intensity output by ultrasonic diagnostic apparatus and received by the embryo in the uterus.Methods　The transient sound parameter and sound field parameter inside the uterus in pregnant rats irradiated by transabdominal color Doppler we re measured with polyvinylidene fluoride (PVDF) piezoelectric sensor.Results　There was a significant difference in the maximal p+(pea k-positive acoustic pressure),p-(peak-negative acoustic pressure),Ispta(inten sity spatial peak temporal peak), Ispta(intensity peak temporal average),Im(int ensity maximum) measured between inside the uterus and in water free field by va rious kinds probes(2.5 MHz,3.5 MHz,7.0 MHz).Conclusions　The irradiation received by the embryo in uterus was smaller than the output of ultrasonic diagnostic apparatus.