The azimuthal response of electromagnetic wave resistivity measurement while drilling with tilted coil was computed via the dyadic Green's function produced by magnetic dipole in a horizontally stratified anisotropic media. The directional phase difference and amplitude ratio signal were defined in a new way. The detection characteristics of apparent resistivity and directional signals were analyzed. The response rules affected by formation boundary,formation contrast ratio,relative dip,anisotropy and coil'...