Abstract: A new type of chaos generator, digital-flow chaos generator is proposed. The strange attractor like ‘helmet’ in Logistic mapping digital-flow chaos generator is found by simulation. The section characteris-tic of Logistic mapping in theory is deduced. And infinitude of immovable points in Logistic mapping chaos section during μ∈(3.57l448,...,4) is found. The basis of chosen parameter for chaotic secure communication is provided.