In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites(BMGCs). The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_(47.5)Zr_(33)Cu_(5.8)Co_3Be_(12.5)(at.%) BMGC was studied by the secondary ion mass spectrometry(SIMS) and the electron energy loss spectroscopy(EELS).It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained. In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti / Zr-based bulk metallic glass composites (BMGCs). The in situ formed β phase in Be-bearing BMGCs was reported to be Be -free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in Ti_ (47.5) Zr_ (33) Cu_ (5.8) Co_3Be_ (12.5) %) BMGC was studied by the secondary ion mass spectrometry (SIMS) and the electron energy loss spectroscopy (EELS) .It is found that Be in almost only dissolves in the glassy matrix, but a very weak intensity of Be in beta phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.