This study proposes a broadband linearization scheme based on a single-drive dual-parallel Mach-Zehnder modulator (SD-DPMZM) to improve the spurious-free dynamic range (SFDR) of microwave photonic link in broadband transmission. The third-order intermodulation distortion (IMD3) is theoretically eliminated using an 180° hybrid, thereby optimizing the biases of the dual-parallel Mach-Zehnder modulator. The simulated results show that IMD3 is completely suppressed when the input signal had two tones. An IMD3 suppression and SFDR improvement of 68 dB and 14.5 dB, respectively, are generated when SD-DPMZM is driven by two radio frequency tones of 10 and 10.01 GHz. Furthermore, results show that SFDR can remain above 114.3 dB·Hz^2/3 when the signal is changed from the X-band to K-band.