Abstract: Using NADPH-diaphorase histochemistry staining, the morphology and distribution of the nitric oxide synthase (NOS) positve neurons in myenteric plexus of goat small intestine were studied at 15 days,4 months and 12 months of age. The results showed that the NOS positive neurons in myenteric plexus of goat small intestine and NOS positive nerve fibers formed clearly a three-class reticular formation. The shapes of NOS positive neurons were different, and lots neurons gathered together, coming into some different size ganglion. With the goats growing, the density of NOS positive neurons in the plexus decreased about 27.07，20.80 and 16.18 neuron/mm2 respectively, but the total number increased about 1.86×106,4.06×106,4.41×106 respectively. The neurons density in the jejunum of different ages was the lower,but the number was the highest. The mean somatic area and nuclear area of the neurons enlarged firstly and then decreased late with goat growing, and the mean ratio between nuclear and plasmic area decreased with growing. There was a notable difference between 15 day-age and 4 month-age, 15 day-age and 12 month-age goat（P<0.05）. The mean somatic and nuclear of the neurons from the duodenum to the ileum showed differences, but the mean ratio between nuclear and plasmic area had no notable difference(P>0.05).