The interaction between diazoresin and sodium dodecyl sulfate(SDS) was investigated in aqueous solution. The results show that with addition of SDS into the diazoresin solution

the complex from diazoresin and SDS forms a precipitate in the ratio of SDS-/N+2 (mol/mol)<0.5

then the precipitate become soluble with the further addition of SDS. It was confirmed that the diazoresin SDS complex solution possesses excellent thermostability as well as high photosensitive behavior and exhibits a powerful latent use as a photosensitive agent in the preparation of negative PS plate.