We report on laser synchronization between a high-power nanosecond fiber laser and an ultrashort Ti:sapphire laser by cross-absorption modulation and power amplification. The nanosecond pulses were generated by a long-cavity ytterbium-doped fiber laser that was passively synchronized to a $70\mathrm{fs}$ Ti:sapphire laser with a remarkable cavity mismatch tolerance of about $8\mathrm{cm}$ as a result of resonance-enhanced cross-absorption modulation in additional rare-earth-doped fiber. By using a two-stage Yb-doped fiber preamplifier and a two-stage double-clad fiber power amplifier in cascade, the synchronized nanosecond pulses were amplified to $131\mathrm{W}$ of average power, corresponding to $0.55\mathrm{mJ}$ of single-pulse energy at a repetition rate of $240\mathrm{KHz}$ , with a timing jitter of $13\mathrm{ps}$ .