BACKGROUND:: It is difficult to combine nano-hydroxyapatite with polyphenylene sulfide by traditional method, thus which is unable to take advantage of nanomaterials. There is still a lack of the research of biocompatibility of nano-hydroxyapatite/polyphenylene sulfide composites. OBJECTIVE:: To prepare the nano-hydroxyapatite/polyphenylene sulfide composites and to evaluate the in vitro biocompatibility. METHODS:: Liquid composite technology was applied to prepare the nano-hydroxyapatit/polyphenylene sulfide composites; infrared spectrometer and scanning electron microscope were applied to analyze the composite constituent structure. Contact angle test, hemolysis test and cytotoxicity test in vitro were conducted with contact angle meter, cony blood and L929 mouse fibroblast cells. RESULTS AND CONCLUSION:: The nano-hydroxyapatite/polyphenylene sulfide composites were intermixed evenly and closely; the composites owned good hydrophilic performance (sheet: 42.5°, powder: 16.1°). The hemolysis ratio of nano-hydroxyapatite/polyphenylene sulfide composites was less than 5% (1.66%), which showed good blood compatibility. L929 cells grew well in the leaching liquor of the composites. The cell counting kit-8 test showed the cytotoxicity in vitro belongs to non-toxic category (level 0-1). All these results prove that the nano-hydroxyapatite/polyphenylene sulfide composites have been prepared successfully and show excellent histocompatibility in vitro.Funding: the Project of Sichuan Health Department, No. 110467; the Scientific Research Key Project of Military Logistics Department during the Twelfth Five-Year Period. No. BWS12J019