The Yb3+ doped double clad polarization-maintaining photonic crystal fiber is prepared from SiO2-Al2O3-P2O5 core glass of an optical fiber perform through a conventional modified chemical-vapor deposition technique and solution doping method, which contains a large core of around 30 m in diameter. Through simulated calculation, the mode area of the double clad polarization maintaining photonic crystal fiber reaches about 232 m2 and the double refraction coefficient B can be 510-5. In experiment, amplification tests of both pulse laser and continuous laser are conducted. The first domestic high efficient femtosecond laser amplification is achieved by using the photonic crystal fiber. A 2 m long photonic crystal fiber laser generates up to 1.64 W output power with a slope efficiency of 49.8%. And 5 m long fiber can reach 8.12 W continuous laser output, in which the slope efficiency is 55.9% and performs good amplification effect. Besides, the extinction ratio is about 10 dB, which indicates good polarization performance of the fiber.