Abstract: Symbol timing delay can be estimated by employing cyclostationarity features of signals. The super performance of estimators is based on large numbers of statistical information. Thus, the observation interval is required to be quite long. However, the performance of estimators become complex when the frequency offset is considered. Due to this problem, the effect of frequency offset and the choice of parameters under this circumstance are studied. Simulation results show that the effect of frequency offset can not be ignored, especially when the observation interval is quite long. In practice, the effect of frequency offset must be considered when choosing the rational parameters.