In order to control the chip formation and improve the chip removal quality of CFRP suction type internal chip removal system， a two-dimensional right angle cutting force model was established. The chip formation process was studied， and the chip shape was predicted and classified.KEYENCE VHX-1000 was used to observe the chips. The results show that the main causes of chip formation are chip bending fracture and shear failure. The chip size is generally between 1.02~1.80 mm. The chip shape is mainly divided into strip chip， micro round chip and meter chip. When the temperature reaches the glass transition temperature of resin， the chip will deform， C-shaped chip and fiber will appear the pull-out phenomenon， the proportion of chips with different shapes is strip chip， micro round chip， C-shaped chip and fiber pull-out chip， except for the rice chip which can not be estimated. The experimental results are in good agreement with the theoretical analysis.