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 has shown many interesting advantages, and can overcome the above limitation. As a result, it can greatly enhance the performance of the frequency conversion system. A broadband microwave photonic frequency conversion technology based on parallel Mach-Zehnder modulator (MZM) and balanced coherent heterodyne detection is proposed in this paper. The common mode noise and the harmonic distortions are suppressed by using balanced coherent heterodyne detection. In addition to the common noise suppression, the advantages brought by both the suppressed carrier modulation and the strong optical oscillator, can significantly improve the SFDR of the frequency conversion system. A spur suppression of 60dB, and a SFDR better than 100 dB?Hz2/3 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.