Aiming at the problems of low spectrum utilization, large equipment volume, poor reliability and complex design in missile borne telemetry communication system, this paper designs a zero intermediate frequency telemetry transmitter with high spectrum utilization CPFSK(Continuous Phase Frequency Shift Keying) modulation. Firstly, according to the CPFSK modulation mode, the framed 2Mbps telemetry data signal is subjected to orthogonal modulation with an index of 0.715. The modulated data is processed by interpolation filtering and upper edge frequency within the AD9364 chip, and then transmitted by the antenna through the amplifier circuit. Finally, the spectrum, transmission distance and bit error rate of the radio frequency modulation signal are tested by the test system. It is found that the output signal has the advantages of narrow bandwidth, concentrated energy of the main lobe spectrum and faster attenuation of the sidelobe, and the transmission distance can reach more than 20Km. The results show that the designed missile-borne telemetry transmitter has the characteristics of small size, low complexity, high reliability and high spectrum utilization. It not only meets the performance index of missile-borne telemetry system, but also can be applied to future aerospace telemetry and remote control system.