Abstract:The main research progress in China and oversea on system analysis and modeling for rice,soybean,alfalfa and their main insect pest ecosystem is surveyed.The objective ecosystems include rice plant and Nilaparvata lugens,Sogatella furcifera,Cnaphalocrocis medinalis,Chilo suppressalis,Tryporyza incertulas,Nephotettix cincticeps;Soybean plant and Anticarsia gemmatalis,Epilachna varivestis,Nezara viridula,Aphis glycines;alfalfa plant and Hypera postica,Agromyza frontella,Hypera brunneipennis, Empoasca fabae.The detail procedure of system analysis for a crop-insect ecosystem is presented.