The magnetic moment of 2＋1 state for 10Be are calculated and investigated in terms of single particle orbits for protons and neutrons under the framework of ab initio Monte Carlo shell model method in an emax=3 model space. The reduced matrix elements of orbital and spin angular momentum are evaluated. It is found that the orientations of orbital angular momentum in different single particle orbits are consistent. Conversely, the orientations of spin in different single particle orbits tend to be chaotic. The nuclear magnetic moment of 2＋1 state for 10Be is obtained as 1.006 ,UN and is discussed in regards to the contribution of orbital and spin angular momentum both for protons and neutrons. The corresponding g-factor is also given.
