The propagator for an arbitrary integral spin

Based on the solution to Bargmann-Wigner equation for an arbitrary integral spin , a further investigation on the projection operator and propagator for an arbit rary integral spins is carried out. The explicit form of the projection operator s for integral spins constructed by Behrends and Fronsdal is checked and confirm ed; the commutation rules and general expressions for the Feynman propagator for a free particle of an arbitrary integral spin are derived.