The lateral line system originates from the embryonic lateral line placode. The specification of lateral line placode requires the collaboration of a variety of signalings. In order to study the role of Wnt signaling in the development of the lateral line system in zebrafish, we modulated the Wnt signaling by heating shock of the transgenic zebrafish, hsp:Wnt8a-egfp and hsp:dkk1-egfp, and evaluated the hair cell number by YO-PRO-1 staining. We found that hair cells in the zebrafish lateral line system cannot form normally after overexpression of Dkk1. Furthermore, we found Wnt signaling was also necessary for precursor cells formation using alkaline phosphatase staining and in situ hybridization of Eya1 and Six2b. In summary, Wnt signaling affects the development of lateral line system through regulating lateral line placode formation.