  We establish the future non-linear stability of
Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) solutions to the Einstein-Euler
equations of the universe filled with a large class of perfect fluids (the
equations of state are allowed to be certain nonlinear or linear types both).
Several previous results as specific examples can be covered in the results of
this article. We emphasize that the future stability of FLRW metric for
polytropic fluids with positive cosmological constant has been a difficult
problem and can not be directly generalized from the previous known results.
Our result in this article has not only covered this difficult case for the
polytropic fluids, but also unified more types of fluids in a same scheme of
proofs.
