PHG is a toolbox for developing parallel adaptive finite element programs. PHG is currently under active development at State Key Laboratory of Scientific and Engineering Computing of Chinese Academy of Sciences. PHG deals with conforming tetrahedral meshes and uses bisection for adaptive local mesh refinement and MPI for message passing. PHG has an object oriented design which hides parallelization details and provides common operations on meshes and finite element functions in an abstract way, allowing the users to concentrate on their numerical algorithms. PHG has a set of rich and easy to use interfaces to other packages, including ParMETIS, PETSc, Hypre, SuperLU, MUMPS, Trilinos, PARPACK, JDBSYM, LOBPCG.