Aiming at the problem of growth and treating of large high quality GaSe infrared crystal，the seed aided vertical Bridgman technique and “puck” cutting method are studied.Finally，boule size of GaSe crystal with 20mm in diameter and 50mm in length is obtained;some samples are prepared under different directions.There are characterized with X-ray diffraction，EDS spectrum and so on.Absorption coefficient about 0.05~0.16cm-1 in the range 1.06~15 μm is achieved.Frequency doubling from 9.3~10.6 μm to 4.65~5.3 μm for a TEA CO2 laser is demonstrated.But how to avoid the deformation of crystals under this cure technique for direct phase matching experiments is still a big challenge.