Pure spinor formalism is a new worldsheet formalism for quantizing the superstring in a super Poincare covariant manner. The formalism provides a powerful way to compute scattering amplitudes. and is very promising for describing superstrings in general Ramond-Ramond backgrounds. In this talk, we try to give an overview of the formalism with some emphasis on my own works. In particular, we try to clarify the structure of the Hilbert space of the formalism.