In this paper the authors proposed three methods to calculate the apparent resistivity for frequency domain controlled source electromagnetic methods. Comparison was carried out involving the analysis of their related theory, 1-D geoelectric forward modeling results and field data. The results show that the wide field apparent resistivity can better interpret the geological base resistivity and has such advantages as strong anti-interference capability but has the shortcoming of complex formula. The far field apparent resistivity with simple formula and likewise strong anti-interference capability gives less information on the base resistivity. At far field and transition zone, the result from the wide field apparent resistivity is similar to that of the apparent resistivity method. The result of the Cagniard apparent resistivity in the far-zone is similar to that of the two methods mentioned above with the simple formula, in which extra magnetic field is required which leads to relatively weak anti-interference capability and poor efficiency. However, the method can not resolve the base resistivity. The comparison of the resolutions on the base resistivity shows that the wide field apparent resistivity is the most favorable method among these methods, followed by the far-zone apparent resistivity, and the last is the Cagniard resistivity. However, the formulas of the last two methods are relatively simpler. The computation cost for the last two methods is less than that of the first one. The inconsistency of the three methods is observed at the far field, which absolutely needs further studies.