To study micro-ecology of respiratory tract among the newborn to investigate effects of different ecological factors on planting of microorganisms at the pharynx of the newborn, and to determinate composition of healthy newborn respiratory tract microorganism bacteria and the superior microorganisms in the pharynx of the newborn. 37 healthy newborn cases with normal growth and their mothers were selected, who had not any family hereditary disease or infectious diseases, and received localization qualitative determination. ①the initial establishment of micro-ecological balance of human respiratory system has certain relations with the delivery method. The Newborn of caesarean birth is asepsis. About 30% newborn carry normal microorganisms from the mother vagina. 3~4 days after their birth, these microorganisms are substituted by normal microorganisms of the streptococcus, without any illness; ② the way of feeding babies doesn’t take any decisive role. In the rural areas, the indoor temperature is unstable and the air pollution is serious. Although play the decisive role in the planting of beneficial microorganisms; ③The season factors have a great influence on the establishment of micro-ecology of respiratory tract, Key Words: ecological factors, neonates; throat; micro-ecology especially in north China, the indoor temperature is stable in urban households, the humidity is low. So the newborn respiratory tract pathogenic bacteria and the condition pathogenic bacteria may survive in newborn′s nasopharynx. Low immunity of the newborns will cause the respiratory diseases. That is the reason why survival rate of the newborn in winter and spring is lower than that in the summer and autumn. ④Swimming doesn’t play a decisive role in the planting of beneficial microorganisms, but it is beneficial to the establishment of good microorganisms. ⑤Pathogenic bacteria proportion is higher in the group of newborn with premature rupture of fetal membrane than that of the normal newborns. Moreover, more pathogenic organisms were detected, which will give rise to infections of newborn′s respiratory tract. Conclusion: Many ecological factors are combined to promote the micro ecological equilibrium establishment of newborn respiratory system, among which delivery method, feeding method and swimming may not affect the microorganisms groups, but the season changes and premature rupture of fetal membrane can bring about greater influences.