Guyed tower is a compliant offshore platform used for drilling and extraction of oil in deep water. This platform has a flexible body and needs proper mooring system to control the deck movements. In present study this platform is analyzed in frequency domain due to irregular waves. The exiting force extracted from Pierson Moskovits spectrum using Morrison Equation. Modeling of moorings is difficult due to their variable stiffness and non linear interaction with main structure. Therefore first using static analysis data the diagram for mooring force–excursion was obtained and fitted to a polynomial of order 5. Then using this equation the spring force of moorings was linearized. Furthermore the drag term was linearized and both of these two linearized terms used in dynamic equation of motion. The results of analysis showed that errors due to these linearization on final results is negligible. Results of this research can be used for optimum design of guyed towers in deep water and its special application in Caspian Sea can be considered.