Vertex Operator of U_q(widehat{B_l}) for Level One

In this paper,we give the explicit formulae of vertex operators of ${U_q}(\widehat{B}_l)$ for level-one as operators on the Fock space. Meanwhile, we point out that the free field realization (by one fermionic field and $l$ bosonic fields) of highest weight module with highest weight $\Lambda_l$ has two irreducible modules.