Abstract: Based on the engineering characteristics of environment discrimination in fuze safe and arming systems, this paper presents such concepts as the information value of environment information sources, the minimum information processing speed required for the operation efficiency of EDD and the minimum quantity of information required to implement the time choosing function of EDD. Furthermore, the rationality of relevant specifications in standards MIL -STD -1316C and GJB373 -87 is analyzed , and the antijamming principle of EDD is put forward based on the concept of information redundance.