The composition,optical and second har monic properties of Er doped GaSe crystals grown by modified Bridgman technology are investigated.It is found that Er content is not uniform in the grow n crystals and much lower than that in the melt compositions.Higher Er doping level makes the optical quality decrease.The spectrum property doesn′t change obviously with Er doping,but the crystal whose Er content equals to 0.07% in mass shows better optical properties in visible r egi on than other crystals.New Raman scattering bands are found in GaSe:Er (0.09% in mass) and GaSe:Er (0.10% in mass) crystals,which are attrib uted to 4F9/2→⁴I9/2 transitions in Er3+ ions through the Raman spectrum measurement.No obvious differences of type I se cond harmonic phase matching angle between pure and Er doped crystals are found with femtosecond Ti:sapphire laser and CO_2laser pumping.The experimental results are in good agreement with the theoretical curves.The seco nd harmonic generation efficiency under CO_2laser pumping is increased by 43% in the optimal doped crystal GaSe: Er (0.07% in mass) among all used samples.The results in this paper may provide reference for the application of GaSe:Er crystals in nonlinear optics and also the research of some other relative doping crystals.