Nano-hydroxyapatite (nHA)/polylactic acid (PLA) bio-engineering materials can be used as alternative material for bone, which has great application in medicine. Nano-hydroxyapatite is main component of bone tissue, has good biological activity, can be used as filler for bone tissue engineering materials; and PLA can be completely degraded in vivo, with good biocompatibility. In this paper, porous nHA / PLA composites were prepared to explore the best nHA addition and efficient method of forming holes. It is found that the porous composite material was prepared by the introduction of ethanol solvent during the dispersion of nHA in PLA. The preparation method is simple, efficient and non-toxic, and the obtained sample has better pore structure. The results of XRD show that nHA could promote the crystallization of PLA, which provides a reference for the crystallization of PLA. At the same time, observing the SEM images found that the experiment to m(nHA)∶m(PLA)≤3∶10 modification is appropriate. And the best addition ratio of m(HA)∶m(PLA)=1∶10, the sample prepared at this mass ratio has better porosity.