In the present work, the influence of turbulence and gravity forces on the tower and the rotor of a 5MW onshore wind turbine has been investigated. A full geometry of the turbine has been designed and simulated in a virtual wind farm and then the fluid loads are imported into the structural part by fluid structure interaction (FSI) method. The final results are shown that the gravity force is significantly higher than turbulence loads and should be considered in designing of the large wind turbines.