Micro-bending with random curvature is usually used to model the mode coupling in few mode fiber (FMF). However, previous models overlooked the accompanied mode dependent loss (MDL) and neglected the order constraints of coupling loss between different modes. In this work, we calculate out the accompanied loss of each mode by using the finite element method. The results show that MDL always increases with bending curvature due to the high-order modes have larger loss than low-order modes. This observation has been confirmed by experiments. Finally, we compare the multi-segment FMFs model with and without considering the accompanied MDL, the results show that micro-bending would degrade the system performance especially when considering the accompanied MDL.