It is shown that the basis of the ellipsoidal acoustic infinite element Burnett method, themultipole expansion, cannot represent real ellipsoidal acoustic field exactly To solve the problem, aweight of angular direction is added to the multipole expansion. The comparison of the modifiedmethod and the prime method shows that the modified method can describe and solve the ellipsoidalacoustic field more accurately than ever A dilating sphere is used to test the new method further.Unlike other infinite element methods, varied ratio of the ellipsoidal artificial boundary instead of sphereis used. The pressure value of the artificial boundary is utilized as the initial value of the new method.Then the radiating phenomena of the ellipsoidal acoustic field can be researched using the new method.These exmples show the feasibility of the adaptive method. It is shown that the basis of the ellipsoidal acoustic infinite element Burnett method, canultipole expansion, can not represent real ellipsoidal acoustic field exactly To solve the problem, a weight of angular direction is added to the multipole expansion. The comparison of the modified method and the prime method shows that the modified method can describe and solve the ellipsoidalacoustic field more accurate than ever A dilating sphere is used to test the new method further.Unlike other infinite element methods, varied ratio of the ellipsoidal artificial boundary instead of sphereis used. The pressure value of the artificial boundary is utilized as the initial value of the new method. The radiating phenomena of the ellipsoidal acoustic field can be researched using the new method. These exmples show the feasibility of the adaptive method.