  We investigate the method for the reconstruction of f(R) gravity models both
from the background evolution observations and from the large scale structure
measurements. Due to the lack of the first principles, one needs to rely on the
observations to build the $f(R)$ gravity models. We show that the general
$f(R)$ models can be specified if the 5\% accuracy level large scale structure
formation observations will be available in the near future.
