Divergence-free　wavelets　with　spline　duals　in　L2(Rn)n　are　constructed　by　using　two　pairs　of　B-splines　with　some　differential　relations　as　the　scaling　functions,　which　are　in　the　sense　of　mild　dual　condition.　Furthermore,　it　is　proved　that　the　projection　of　an　incompressible　flow　field　remains　divergence-free　property.　Finally,　a　specific　example　is　given.