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By applying the fixed point theorem in a cone of Banach space, we obtain an easily verifiable necessary and sufficient condition for the existence of positive periodic solutions of two kinds of generalized n-species competition systems with multiple delays and impulses as follows: xi′(t)=xi(t)[ai(t)-bi(t)xi(t)-∑j=1ncij(t)xi(t-τij(t))-∑j=1ndij(t)xj(t-γij(t))-∑j=1neij(t)∫-σij0‍fij(s)xj(t+s)ds], a.e., t>0,t≠tk, k∈Z+, i=1,2,…,n; xi(tk+)-xi(tk-)=θikxi(tk), i=1,2,…,n, k∈Z+;  and  xi′(t)=xi(t)[ai(t)-bi(t)xi(t)+∑j=1ncij(t)xi(t-τij(t))-∑j=1ndij(t)xj(t-γij(t))-∑j=1neij(t)∫-σij0‍fij(s)xj(t+s)ds], a.e., t>0, t≠tk, k∈Z+, i=1,2,…,n; xi(tk+)-xi(tk-)=θikxi(tk), i=1,2,…,n, k∈Z+. It improves and generalizes a series of the well-known sufficiency theorems in the literature about the problems mentioned previously.