The hybrid system WDM Radiofrequency over free space optics\fiber optic (RoFSO\FO) is one of the modern technologies that support developing the 5th generation for the communication network. The WDM RoFSO\FO system is designed to transmit high data rates over a long distance under variable weather conditions (fog, dust, and rain). Where the attenuation caused by atmospheric changes is one of the most important obstacles faced the FSO channel. The spatial diversity technique is used by sending multiple copies across the free space to improve system performance. The hybrid design tested the performance of 16 channels optical transmission, each channel transmits 2.5Gbps data rate modulated by PSK modulator on a 20GHz radio frequency signal. Where 40 gigabits per second was transmitted via 4000m multi-channels FSO extending to 120 km optical fiber as a total distance, 80 km of which was amplified by Raman / EDFA hybrid optical amplifier. The bit error rate BER and the Q-factor monitored and compared with the standard Kim model. From the results obtained by using the OptiSystem simulation, an improvement in the system was found significantly by increasing the transmission capacity when using WDM technology and long-distance transmission under variable weather conditions without adding a light source.