The symmetry of lattice points in a two-dimensional topological photonic insulator has not been explored as a design freedom. In this study， the influence of the symmetry of the lattice points on the photonic bandgap of an all-dielectric valley photonic crystal （VPC） structure is analyzed by using elliptical lattice points with lower symmetry. The central wavelength and width of the photonic bandgap of the VPC can be modified by varying the direction of the long axis of the elliptical lattice points. The all-dielectric VPC structures with different bandgap widths and central wavelengths are combined in a mirror-symmetrical manner to form all-dielectric photonic topological insulator waveguides， which achieve anti-scatter robust unidirectional optical transmission. This study adds new degree of freedom and provides new possibilities to all-dielectric VPC designs.