"A Bi-level Frequency Hopping Code-Division Multiple-Access (FH-CDMA)" scheme for wireless communication systems is developed. This new scheme provides flexibility in the selection of modulation codes and FH patterns. By partitioning modulation codes, our Bi-Level FH-CDMA scheme can be modified to support more possible users without increasing the number of FH patterns. This scheme is applied for different Fading channels and their performances in terms of Bit Error probability (BEP) are compared. We also calculate Spectral Efficiency (SE) of this scheme and compare this with Spectral Efficiency (SE) of Goodman's Frequency-Shift-Keying FH-CDMA. Our results show that the partitioned Two-Level FH-CDMA scheme supports higher data rate and greater SE than Goodman's Frequency-Shift-Keying FH-CDMA scheme under some conditions.