The writers conducted a study about the synthetic and characterization of poly(lactic acid)/ethyl cellulose/hydroxyapatite composite with the addition of sodium trimetaphosphate as a cross-linker for bone scaffold application. The purpose was to find out the impact of sodium trimetaphosphate concentration variation on scaffold to get the best mechanical and physical properties to be applied as bone scaffold in accordance with standard. This research was conducted by using a simple mixing method and freeze drying as the equipment for drying purpose. Scaffold was soaked in a solution of sodium trimetaphosphate with the concentration variation are 6%; 8%; 10%; 12%; 14% w/v. The characterization of mechanical and physical properties test at scaffold showed the characteristic which meets the standard of mechanical and physical properties for human bone. The result of FTIR spectra indicate the presence of formed chemical bond between cellulose and sodium trimetaphosphate. According to the result, the best performance of scaffold was obtained by 14% sodium trimetaphosphate concentration, which has a pore size value of 100-249 μm, compressive strength 5.37 MPa and porosity 63.17%. Based on the result of the characterization, scaffold with the addition of sodium trimetaphosphate as a cross-linker have fulfilled criteria for bone regeneration.