Abstract: The residual dynamics of S-7802 pesticide in rice and paddyfield was studied in Sichuan during 1988-1990. The results showed that S-7802 pesticide degraded rapidly in rice and paddy field and more than 90 %was degraded within 7 to 9 days after application with rate of 100 g a. i/mu. Thehalflife of S-7802 degradation was 2 days in rice. The maximum of s-7802 residue in rice was less than 0. 5 ppm used at 75 g a. i. /mu for 1 to 3 timesduring the experiments periods.