The long-wave transmitting antenna can be regarded as a top loaded monopole antenna and a common form of antenna has the umbrella antenna and inverted-cone antenna. Based on the four tower inverted-cone antenna as an example, the composition of antenna is introduced and the selection of the key parameters is discussed, and a specific solution is presented by the numerical analysis method. Based on the scheme, the scale model test is carried out, the accuracy of antenna design is verified, and the characteristics and design method of the modified antenna are mastered.