The surface-profile precision of objective lens for lithography is a key factor which influences the imaging quality. In order to achieve the root-mean-square (RMS) value of lens surface-profile accuracy which is better than 2 nm, a novel lens support structure with multi-points axial flexible support and three-point length-changeable radial holding is proposed, and then structure optimization by the influence of gravity deformation compensation is realized. Finally, the finite element analysis of lens deformation due to gravity and thermal load is done. The results are as follows: for the deformation of lens surface caused by gravity, profile RMS of the upper surface is 0.186 nm, while RMS of the lower surface is 0.15 nm; for the deformation of lens surface caused by thermal load, profile RMS of the upper surface is 0.55 nm, while RMS of the lower surface is 0.54 nm. The results indicate that the lens supporting structure can meet high-precision requirements of surface profile of the objective lens for lithography.