Enhancing coherent combining efficiency via choosing appropriate lasing wavelength in a Michelson compound cavity based on two 3 dB fibre loop mirrors and one fibre Bragg grating(FBG)has been experimentally demonstrated.The FBG with 4.5% reflectivity is replaced at the cleaved facet with 4% Fresnel reflection.A high coherent combining efficiency of 93.5% is obtained when the FBG with central wavelength at 1559.845 nm is introduced into the cavity, while it is only 90.1% combining efficiency with the FBG at central wavelength 1557.830 nm.In comparison with other reports,the proposed compound-cavity laser has the advantage of needless tuning FBG to obtain the coherent condition,and it is facile to ascertain the seemly wavelength lasing for a Michelson compound cavity.