Natural enemy-

Cnaphalocrocis medinalis

(Guenee) system was studied based on the principle and method of system sciences to seek possible ways or strategies for pest population control. Conceptual model describing interrelated or interacting activities among different generations of

Cnaphalocrocis medinalis

Guenee) and their natural enemy was established and further quantified with differential equations or function formulas. Dynamics of

Cnaphalocrocis medinalis

(Guenee) and natural enemy population density were simulated and analyzed respectively using STELLA. The results indicated that trends of both

Cnaphalocrocis medinalis

(Guenee) and natural enemy population in six pest-control scenarios were different in their peak values and occurrence time

etc. A considerable quantity of natural enemy was essential to the effective control of occurrence and development of

Cnaphalocrocis medinalis

(Guenee)〖WTBX〗.〖WTBZ〗 Supplement of a number of natural enemy to rice cropping field at the early period of insect pest occurrence were recommended for enhancement the control on

Cnaphalocrocis medinalis

(Guenee) during the late growth period of paddy rice.