Several polybutadiene samples prepared with different catalysts Were studied by 13C-NMR. It is shown by analyzing the molecular chain of polybutadiene that there are three sequences (cis 1

4-sequence

trans 1

4-sequence and 1

2-sequence) and seventeen aliphatic carbon nuclei in it. These nuclei contribute to the sixteen peaks on the 13C-NMR spectrum of polybutadiene. A group of empirical parameters is obtained by analyzing the chemical shift data of the peaks. When using them in our case

the calculated values of chemical shift of the peaks agree quite well with the experimental ones. A T4peak

the fouth peak oftrans 1

4sequence

was first discovered by the present work.Quantitative treatment of the se-quence structure ofpolybutadiene was preliminaryly studied.