By using a fixed point theorem on strict-set-contraction, some sufficient conditions are obtained for the existence of positive periodic solutions for a periodic neutral functional differential equation on time scales of the form
xΔ(t)=x(t)[r(t)-a(t)x(t)-∑nj=1aj(t) x(t-τj(t, x(t)))-∑nj=1cj(t) xΔ(t-σj(t, x(t)))g ],
where r, a, aj, cj ∈C( T, R+)(j =1, 2, … , n) are ω -periodic functions, and τj, σj ∈C( T×R, T)(j =1, 2, … , n) are ω -periodic functions with respect to their first arguments, respectively.