In order to solve the contradiction between the outofband rejection and the linear phase ripple in the passband, a design method of linear phase LC filter is introduced in this paper. Based on the analysis of the transmission zeros of the filter, the circuit topology and zeros position are designed flexiblyaccording to the requirements of the specifications. The filter with high rectangular coefficient and linear phase characteristics is realized by using the cascade network of internal and external equalization circuits.Two filters with a center frequency of 21.4 MHz, a 0.5 dB bandwidth of greater than 10 MHz, a rectangular coefficient(45 dB/0.5 dB)of less than 2, the absolute value of the inband phase ripple of less than 5° and a central frequency of 1 300 MHz, a 1 dB bandwidth of greater than 200 MHz, a rectangular coefficient (35 dB/1 dB)of less than 2, and the absolute value of the inband phase ripple of less than 5° are designed. The proposed method is practical in engineering, easy to debug and manufacture, and can be applied to microwave systems with high amplitude and phase characteristics, which can improve the system performance.