Abstract: The essentiality of a protein is correlated with its topological properties in a bionetwork. Viewing the identification of essential proteins as a special kind of pattern recognition by setting up the quantification of the relationship of molecules --- topological parameter, this paper analyzes the correlation between a protein's essentiality and its main topological parameters, studies the nature of the essential-node-judgement of the parameters, puts forwards theoretically the relation between the identification degree of combined parameters and that of the single parameters involved and the correlation between single parameters, and gives effective construction methods of combined parameters and their asynchronous recognition algorithm. The results show that the identification ability of the technique is obviously greater than that of the others.