We propose a new type of high flexible single-polarization single-mode (SPSM) photonic crystal fibre (PCF).Numerical analysis indicates that the SPSM PCF proposed guides only one polarization mode over a wavelength band broader than the conventional SPSM fibres. The position and the bandwidth of the single polarization mode region depend flexibly on the structure parameters such as the hole diameters d1 and d2 and the hole pitch A of the SPSM PCFs. A 200-nm SPSM region can be obtained for the SPSM PCF with A = 2.55 tm, d1/A = 0.3and d2/A = 0.833 and the modal birefringence at the wavelength 1.31 μm can reach 1.8 × 10-3.