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.. -species competition systems with multiple delays and impulses as follows: x(i)(t)(t) = x(i)(t)[a(i)(t) - b(i)(t)x(i)(t) - Sigma(n)(j=1) c(ij)(t)x(i)(t - tau(ij)(t)) - Sigma(n)(j=1) d(ij)(t)x(i)(t - gamma(ij)(t)) - Sigma(n)(j=1) e(ij)(t)integral(0)(-sigma ij) f(ij)(s)x(j)(t + s)ds], a.e., t > 0, t not equal t(k), k is an element of Z(+), i = 1,2,..., n; x(i)(t(k)(+)) - x(i)(t(k)(-)) - thet...