To generate millimeter-wave (mm-wave) signals with arbitrary and tunable frequency multiplication factors (FMFs), a photonic approach is proposed. Firstly, a Dual-driving Mach- Zehnder modulator (DD-MZM) and a phase modulator (PM) are used to produce an optical frequency comb (OFC). Then an acousto-optic tunable filter based on the uniform fiber Bragg grating (UFBG-AOTF) chooses the optical carrier and two symmetric harmonics from the OFC. Finally, the characteristic of an optical band-stop filter (OBSF) followed the UFBG-AOTF determines whether the mm-wave is arbitrary times or even times of the local frequency. For even-times FMF, mm-wave with a frequency up to 28 times of the LO frequency can be generated. Also, for the arbitrary-times FMF, mm-wave up to 11 times of the LO frequency can be obtained in principle. The flexible tunability of FMF can be achieved by controlling the frequency of the signal applied on the UFBG-AOTF. Mm-waves with FMF of 11 and 22 are both generated by simulation. Results of the research show that the 2-Gbit/s data can be successfully transmitted over 50km single mode fiber with power penalties of only about 1.72dB and 0.81dB, separately. Moreover, the generated mm-wave with the FMF of 28 has a sideband-suppressed ratio (SSR) higher than 20dB, which is enough for a normal communication.