Abstract: Objectives  To investigate the correlation between dietary fatty acids intake of pregnant women and neonatal  anthropometry at birth. Methods Women in early pregnancy were recruited with appropriate value of weight gain in pregnancy.  Instant photography was used to assess the dietary situation in both the second trimester and the third trimester to calculate the  intakes of food, energy, macronutrients, and fatty acids. The body weight, height and BMI at birth were evaluated with Z scores. The  correlation between dietary fatty acids of pregnant women and neonatal anthropometry at birth were analyzed. Results There were  516 pregnant women recruited in this study. The average intakes of polyunsaturated fatty acids (PUFA) and the proportion of total fatty  acids in the two trimesters were 15.09 g/d, 23.93% and 17.18 g/d, 24.86%. In the second trimester the intakes of n-6 and n-3 PUFA  were 14.23g/d and 3.45g/d, and in the third trimester, n-6 and n-3 PUFA were 16.08g/d and 3.81g/d, the average intakes in the  third trimester were significantly higher than those in the second trimester (P?＜?0.05).n-6/n-3PUFA ratio was 4.11 and 4.28?in the second trimester and the third trimester, respectively, without  significantdifference between the two trimesters (P?>?0.05). The intake  of DHA (64.43mg/d) in the second trimester was lower than that in the third trimester 75.12 mg/d, (P?＜?0.05). The percentage of  linoleic acid (LA) and α-linolenic acid (ALA) contribution to energy were 5.95%, 1.42% and 6.20%, 1.45% in the second and  the third trimesters, respectively. There was no significant difference between the two trimesters (P?>?0.05).The dietary intakes of  n-3 PUFA, n-6 PUFA and n-6/n-3 ratio in the second trimester were positively correlated with neonatal BMI r =0.142~0.189,  P?＜?0.05). But in the third trimester, only n-3PUFA and DHA were positively correlated with birth weight ( r =0.206, 0.193, P?＜?0.05); there was no correlation between n-6/n-3 ratio and neonatal BMI ( r =-0.018, P?>?0.05). Conclusions The dietary ratio of n-6/n-3 PUFA in  the second trimester was positively correlated with neonatal BMI, suggesting that moderately increasing the intake  of n-3 PUFA may play a positive role in reducing childhood obesity.