Based on two syntactic dependency treebanks built with two different styles of Chinese, a statistical study is conducted regarding word-frequency and distributions. We extracted three grammatical words as the research objects and analyzed their network features, including all degree, out-degree, in-degree, all closeness, in-closeness, out-closeness and betweenness. Then these three nodes were removed from the networks. We recorded and compared the network features of the two original networks and the three networks from which one node is respectively removed, including the number of vertices, average degree, average path length, diameter, the number of isolated vertices, domain and density. The results show that all three function words are central nodes of the Chinese syntactic networks but have different status. Their influence to the overall structure is also quite different. The research not only provides a new method for the study about Chinese grammatical words but also provides a new way of thinking the node characteristics in the complex network.