  In this paper, the photonic quantum spin Hall effect (PQSHE) is realized in
dielectric two-dimensional (2D) honeycomb lattice photonic crystal (PC) by
stretching and shrinking the honeycomb unit cell. Combining two honeycomb
lattice PCs with a common photonic band gap (PBG) but different band topologies
can generate a topologically protected edge state at the combined junction. The
topological edge states and their unidirectional transmission as the scatterers
with triangular, pentagonal, and heptagonal shapes are researched. Meanwhile,
the unidirectional transmission in an inverted {\Omega}-shaped waveguide with
large bending angle is realized, and verifies the characteristics of the
topological protection by adding different kind of defects. Moreover, the
frequency varies significantly when changing the scatterers shape, which shows
that the PC with various scatterers shape can tune the frequency range of the
topological edge state significantly. In other words, it can adjust the
frequency of unidirectional transmission and increase the adjustability of the
topological edge state.
