Objective To study the effects of hypoxia in uterus on nNOS expression in postnatal mouse parietal cortex and the learning and memory ability of adult mouse. Methods The number and shape of parietal cortex neurons during postnatal development with hypotonic hypoxia in uterus were observed by Nissl staining. The expression of nNOS in parietal cortex neurons during postnatal development with hypoxia in the uterus was studied with immunohistochmistry. The ability to learn and memorize in adult mouse was observed by Morris water maze. Results Compared with the control group, the number of neurons in parietal cortex from mouse during postnatal development in hypoxic group reduced significantly（P<0.05）and the expression of nNOS in parietal cortex neurons during postnatal development in the hypoxic group decreased significantly (Ｐ1，P<0.01； Ｐ7，P<0.05； Ｐ14，P<0.05； Ｐ28，P<0.01； Ｐ90，P<0.01). The period from latency to escape platform was prolonged (1 day,2 days, P<0.05; 3 days,4 day