Abstract: According to the principle that temperature, humidity, season and host influenced the development in vitro of soiltransmitted parasitic nematodes, the regression analysis on the above factors and the speed and number of Marshall wireworm from egg to invasive larva was made. The simulation model was made and the prediction formula on the number of Marshall wireworm from egg to invasive larva was designed. The seasonable dynamic curve of invasive larva was calculated by applying meteorological data in the formula. And it was compared with the dynamic curve of adult number in sheep in the grassland. The research showed that the seasonal changes of the number of invasive larva of Marshall wireworm in grassland could be predicted by using computer processing with meteorological data, which could provide scientific basis for making control measures.