The Niangniangshan alkaliue series occurs in the Niangniaugshan caldera, which is located in the centre of the Ningwu volcanic basin, and surrounded by ring fractures. The volcanic rocks in the caldera are getting younger from outer to inner, The major rock types include trachyte, high-potassium phonolite, hail- ynite phonolite and subvolcanicintrusive rocks. This series is high alkaline, silica-undersaturated and very rich in LREE. The initial ratios of 87Sr/86Sr and ∈Nd range from 0.7070 to 0.7073 and-3.4, 一3.3 respectively. The quantitative modelling shows that;(1 )the source rocks of hailynite phonolite and aegirine augite syenite are the mixtures of upper crust and depleted mantle, being 41% and 59 % or 42% and 58% respectively;(2) the primary magma of the alkaline series was formed by partial melting of source rocks, the degrees of partial melting being 6.4%and 6.6%.The modelling provides probable quantitative geachemical model for diagenetic process of the alkaline series.