Abstract: By a field inoculation and laboratory experiment,the ecological factors effected the quantity of parasitic nymph of M.matsumarae are studied.The results indicate that high temperature in the summer is the key factor.The colony quantity of perasitic nymp vary in different generations obviously.Temperature in the spring suits for its propagation and existence,for its death rate over 90% at high temperature in the summer.The nymph's ability to endure high temperature isn't as strong as it against low temperature.Two linear equations are developed to show the Close relationships respectivly between the intensity of light and nymph's death rate and between the surface temperature and the death rate.