The conventional frequency conversion of satellite payloads in electronic domain has the drawbacks such as susceptible to electromagnetic interference, limited spur-free dynamic range (SFDR), as well as narrow band. The introduction of microwave photonic into satellite communication system has shown many interesting advantages, overcoming the limitations of signal frequency conversion in electric domain and improving the performance of the on-board frequency channel. A broadband microwave photonic frequency conversion technology based on parallel Mach-Zehnder modulator (MZM) and balanced coherent heterodyne detection is proposed in this paper. Better common mode noise suppression and reduced harmonic distortions were achieved by using balanced coherent heterodyne detection. While combining the advantages brought about by the suppression of carrier modulation, the SFDR of the frequency conversion system were significantly improved. A spur suppression ratio better than 60dB and a SFDR better than 100dB·Hz2/3 in microwave photonic frequency conversion system is proposed and experimentally demonstrated. Essential theoretical basis and technical support are provided for the new scheme of microwave photonic frequency conversion of satellite payloads.