Let(Mr,T)be a smooth closed manifold of dimension r with a smooth involution T whose fixed point set is F=HP1(2 m)∪HP2(2 m)∪HP(2n+1)(m≥1),where HP(n)denotes the n-dimensional quaternionic projective space.By constructing symmetric polynomial and computing characteristic number,it is proved that when r>8 m+8n+8,every involution(Mr,T)fixes Fbounds.