The interest in graphene is connected with a number of its unique properties: electronic, optical, mechanical, thermal ones. Two-dimensional ideal graphene cannot be obtained in free state due to the thermodynamic instability of its structure. However, if such film has defects or if it is deformed in the third dimension, this «nonideal» film can exist without the contact with substrate. Free graphene films exist and form a wavy shape surface, but on the whole deformations origin and nature remain the subject of discussions. These waves exert a direct effect on the properties of the material and therefore control over the morphology of graphene is followed by the control over its properties. Complex high-precision and expensive equipment is required for real experiments and study of this problem on nanoscale objects. That is why simulation of graphene is of immidiate interest. In this paper computer simulation of relaxation of two types of graphene nanosheets of 7,2 × 7,2 nm and 14,4 × 14,4 nm size has been carried out in two modes of relaxation — electromechanical and mechanochemical. Mean square deviation of carbon atoms from their original position has been calculated. Complex of computer simulations has showen significantly different behavior of graphene nanosheets in two limit modes of relaxation.