Abstract: In order to estimate the damage threshold index and sampling technique of Chinolyda flagellicornis, we conducted studies on their life cycle ，leaf consumption, spatial distribution pattern and sampling technique, through leafpicking simulated damage experiment. The result showed that they breed one generation per year, mature larvae turned into prepupae to live through summer and winter beneath the earth. The period of larvae damage span the mid of May to the first ten days of July, when they are in 7th instar, the diapause period can be 290—330 d. The feeding observation indicates that each larva consumes 3.64 g on average, and 84.26% are consumed by larvae in 5th—7th instar. Fresh leaves quantity and DBH of Cupressus funebris were of the relationship as W=551.477 2+360.599 6D+58.947 2D2. The analysis of variance and multiple comparison of leafpicking simulated damage experiment reveal that 35% and 50% loss of leaves causes no significant difference in the aspects of DBH and height increment. However, the difference in volume increment is remarkable, 50% loss of leaves has large imparity, while the 35% one is not. Thus 35% of leaveloss is confirmed to be the damage threshold level, the damage threshold index of larvae is calculated according to the leafconsumption and fresh leaves quantity. and the one of larvae in diapause is according to the formula of the propagation amount. Its spatial distribution pattern is characterized by aggregated distribution of the diapause larvae, and the ental constituent of distribution is individual population. the theoretical sampling number and sequential sampling method are fixed according to the value of α and β in Iwao’s model and the index of damage threshold. No significant differences are noticed between the use of diagonal, Zshaped and paralleled measurements.