Abstract: Shaking table process is applied to evaluating biodegradability of four cationic surfactants M-300，M-301，M-302 and lauryl .The results showed that the net biodegradability rate of the four cationic surfactants in twenty days is 44.04%、72.65%、32.14%、76.98% respectively. according to the evaluation standards， M-301 and lauryl amine are easily biodegradable， while M-300 and m-302 is biodegradable.

Key words: cationic surfactant, Shaking table, biodegradability