In order to study the relationship between rock breaking efficiency of TBM and the shapes of rock chips, the linear cutting test is carried out on Beishan granite by mechanical rock breaking test platform. The analytical results of coarseness index, flatness and long axis of rock chips show that the shapes of rock chips can reflect the rock breaking efficiency of TBM. The higher the rock breaking efficiency of TBM is, the longer the long axis of rock clip is, the larger the coarseness index of rock clip is and the flatter the rock clip is. The coarseness index and specific energy show linear relationship by regression analysis. The rock breaking efficiency of TBM reaches the highest when the ratio between spacing of cutters and penetration rate is 40. The results show that the analysis of rock chips is very important for evaluation of rock breaking efficiency of TBM and construction optimization.