In this letter, we experimentally demonstrate the generation of W-band millimeter-wave (mm-wave) vector signal based on frequency quadrupling and balanced pre-coding technology by a single-driven Mach-Zehnder modulator (MZM). The MZM is biased at its maximum transmission point, and it is driven by a 22-GHz QPSK vector signal with balanced precoding. In addition, 1-/2-GBd QPSK vector signal at 88 GHz is generated after wavelength-selective-switch selection and single-ended photodiode detection. The experimental results show that, after 0.5-m wireless transmission, a bit-error-rate (BER) below than 1e-3 can be achieved. To the best of our knowledge, it is the first time to report the generation of the W-band mm-wave vector signal by using frequency quadrupling and balanced pre-coding technology.