By using T63L9 model and breeding mode growth method(BGM),the ensemble prediction of typhoon track has been carried out, and the research of the breeding length which is the key technology of BGM has been done. The result shows that the ensemble prediction by using BGM is able to improve the skill of typhoon track prediction in contrast with the control prediction. The different breeding length in ensemble prediction has some influence on the prediction effect of typhoon track. When the breeding length is selected as 2 or 3 d, the effect of ensemble prediction is better than control forecast. When the breeding length is 3 d, the measure of ensemble spread is reasonable. But when the breeding length is selected as 4 d, the measure of ensemble spread is too small. In a word, the prediction effect of breeding for 2 d or 3 d is better than control forcast. The ensemble prediction breeding for 3 d is more reasonable. When the breeding length is selected as 3 d, the typhoon track error of ensemble prediction is about 100 km in the first 3 d, which is only close to 300km in the fourth day.Compared with the control forecast, the correction of ensemble prediction can reach over 60%,and even 70% in the 2-4 d.