Fourier transform infrared spectroscopy and chemical analysis were applied to study the chlorination reaction mechanism of latex．The results showed that the chlorination mechanism of latex is similar to that from solution：(1) substituted chlorination and cyclization (The initial substitution was created by that chlorine attacked natural rubber molecules with concomitant cyclization reaction)

(2) addition-elimination accompanied by a shiftiog of the C=C group and (3) pure substitution．Furthermore

the production of ClC—C=O and RClC—COOH groups was recorded by Fourier transform infrared spectroscopy．This is the largest difference between CNR prepared from latex and from solution．From the ratio of primary

secondary and tertiary C—Cl bands analyzed by 13C—NMR

combined with IR spectrometry and high resolution pyrolysis gas chromatography-mass spectrometry．the chlorination mechanism of CNR from latex and the sequence of —Cl substitution and addition could be introduced．The structure of CNR from latex is not as regular as CNR from solution．The main reason was that HOCl formed at the initial stage of chlorination

and RClC—COOH produced at the later stage of chlorination．Furthermore

a conclusion could be deduced that the chlorination reaction takes place evenly on all NR molecules in the chlorination process in latex．