Let(RPn,F)be a bumpy and irreversible Finsler n-dimensional real projective space with reversibility λ and flag curvature K satisfying(λ/1+λ)2<K<1 when n is odd,and K≥0 when n is even.We show that if there exist exactly2[n+1/2]prime closed geodesics on such(RPn,F),then all of them are non-contractible,which coincides with the Katok's examples.