Effects of LTI addition on the mode I fracture energy of HA/PLLA/PCL were examined and the micro-structural modification due to LTI addition was investigated. Both the mode I energy release rate, G (in), and averaged fracture energy, E (f), are improved dramatically due to LTI addition. The reason is considered to be the improvements of the interfacial structure connecting HA particles with PLLA/PCL matrix and the miscibility between PLLA and PCL. These changes of blend morphology and interfacial structure reduce the stress concentration and lead to the ductile deformation and resulted in the increase of those fracture properties.