Bad cement bond with water channeling or low strength cement is usually generated on the first and/or secondary interfaces which lie between the cement and casing, and the cement and formation, respectively. It is an inherently complicated problem to evaluate cement bond on the secondary interface (SICB) in a cased borehole. So we need to find a useful wave for evaluating SICB and provide its propagation features. To achieve this, we simulated the acoustic full waveform, 2-D spectrum and dispersion curves in cased boreholes based on the real axis integration method, and a propagator matrix. Simulation results indicated that “casing-cement mode” wave can be utilized to evaluate SICB, as it is most sensitive to water channeling on the secondary interface. Velocity of this mode wave is in between that of the casing wave and the formation wave, so that it is easy to extract it in time. The dispersion curves showed that the casing-cement wave is a dispersion wave, but not a pseudo-Rayleigh wave. Its velocity is obviously larger than v s of cement. Simulation results further indicated that the amplitude of casing-cement wave is decreasing with increasing cement sheath thickness, but not water channeling thickness, and its travel time is influenced by casing and cement together. Moreover, we investigated factors influencing the casing–cement wave and found that casing diameter and peak frequency are major factors influencing the amplitude and the travel time, while other factors, such as P-wave velocities of cement and wall thickness of casing, are minor factors. But none of these factors greatly influence bond index which is computed from the amplitude. So the bond index has an advantage over the amplitude during evaluating SICB. Formation wave is a helpful signal to evaluate low strength cement without water channeling, and its amplitude is mainly related to the velocities (or impedances) of both cement and formation except for formation attenuation and disturbance wave. Experimental data in calibration pits and field data detecting channeling demonstrated the simulation results.