This paper presents a method to design a crystal filter which has the characteristics of high reliability, high fundamental frequency and small group delay. In order to realize a small group delay and a small rectangular coefficient at the same time, a method to control the attenuation peak using fewer components than usual filter was adopted. Meanwhile, in order to achieve a high reliability, and ion etching technology was used to manufacture a high fundamental frequency crystal resonator. Magnetizing treatment was used to realize the completely sealed construction of the filter. The operation frequency of the filter was 70 MHz, 3 dB widthband was 151.4 kHz, the ripple in the pass band was less than 0.5 dB, the group delay was less than 3 μs between the frequency of 69.95 MHz and 70.05 MHz, the rectangular coefficient was less than 2.8.