Effect of catalyst content,reaction time and temperature on synthesis of boron modified phenolic resin was investigated and the relationship between mechanical properties of carbon fiber reinforced boron modified phenolic resin(CF/BPR) composites and carbon fiber(CF) content and surface treatment were studied.The results show that boron modified phenolic resin with(diffe)-(rent) boron content could be synthesized under special technology condition.Flexural strength,flexural modulus and impact strength of CF/BPR composites increase with increasing CF content.Flexural strength,flexural modulus and impact strength of CF/BPR composites reach to maximum when CF content is 30%.Flexural strength and flexural modulus of CF/BPR composites increase when the surface of carbon fiber is treated,but impact strength of CF/BPR composites decreases slightly.