Abstract: Population growth of Thrips palmi Karny on eggplant (Solanum melongena L.) were analyzed by mathematical models.The rate of population increase (r) of the adults and immature (instars 1～2) T.palmi were estimated to be 0.0630 and 0.0801 respectively in the open fields, and 0.0983 and 0.1036 respectively in the greenhouse. K value of logistic curve of T.palmi was estimated to be 33.90 in the greenhouse, and 23.50 in the open fields. The relationship between mean crowding (M^*) and mean density (M) of T.palmi per eggplant leaf were estimated by Iwao's M^*-M regression.The regression equation of adult and immature T.palmi on eggplant were:M^*=0.6011+1.468M and M^*=7.2515+2.064M respectively. The regression equation of the number of adult and immature was M^*=7.5138+1.9119M.When the population density of the adults and immature T.palmi per eggplant leaf were 10 to 100, the number of sampling should be 78 to 44.