Abstract: Several studies on the micro-and crystalline structure of solution-and suspension-chlorinated polyethylene(CPE) have appeared in literature.This paper presents our study on the structure of solid phase chlorinated powder polyethylene by means of ¹³C-nuclear magnetic resonance, infrared spectroscopy, pyrolysis-gas chromatography and differential scanning calorimetry.The results show that chlorination of the samples with low chlorine-content was hindered-type substitution,while that of the samples with chlorine content over 50 wt% seemed to be more complicated. The molecular chains of thesc CPE mainly composed of-CH₂-and-CHCl-groups; only in the samples with chlorine-content over 50 wt% appeared-CCl₂-groups, the quantity of which,however,was extremely small. The change of crystallization behavior of these CPE was different from both the solution-chlorinated and the suspension chlorinated polyethylenes.