Objective:The ultrasonic measurement of fetal prenasal thickness(PT)and nasal bone length (NB), to investigate the growth law, the range of normal value of each gestational week’s PT and NB. Methods:From 2012 January to December in our hospital, 2158 cases of prenatal ultrasound examination of pregnant women,observe and recorde the fetal nasal bone’s development, measure PT and NB, analysis the relationship between the two, and then analyze relationship with gestational week. Results:PT and NB values increased with the increase of the gestational week. The correlation coefficient of PT and gestational week is 0.769(P<0.01), the correlation coefficient of NB and gestational week is 0.748(P<0.01), the correlation coefficient of PT and NB is 0.694(P<0.01). Conclusions:Fetal PT and NB increased with gestational week, and with the gestational weeks was linearly related;PT and NB is linear correlation.