This paper studied the effects of polymerization conditions on polymerization of high isotactic polybutene-1(i-PBt) in the presence of a TiCl4/MgCl2AlEt3 catalytic system,and the as-synthesized high i-PBt was characterized by DSC and FTIR.The results showed that isotacticity of polymer increased at first with the increase of n(DDS)/n(Ti),and then decreased.Isotacticity reached a maximum while the n(DDS)/n(Ti) equals to 1.3.The same trend happened to the hydrogen pressure,and isotacticity reached maximum when the hydrogen pressure equals to 0.04 MPa.Under this hydrogen pressure,we can synthesize i-PBt with isotacticity of 94.1% while the ratio of n(DDS) to n(Ti) is 1.3.The as-synthesized i-PBt was compared with commercial sample by DSC and FTIR,result showed the as-synthesized i-PBt had extremely approached to foreign commercial sample.