We propose a novel highly birefringent photonic crystal fiber (PCF). It is composed of a triple defect core and a cladding with squeezed hexagonal lattice circular air holes. Using a full-vector finite element method (FEM) simulator (COMSOL Multiphysics), we study the modal birefringence of the fundamental modes in such PCFs. Numerical results show that the birefringence of the proposed PCF reaches the order of 10-2, which is larger than the triple defect core PCF without squeezed cladding, also is much larger than the single defect core PCF with squeezed cladding. Moreover, the proposed PCF also has a low confinement loss about 10dB/km at wavelength λ=1.55μm.