Stable ZrC sol was prepared by sol-gel method using zirconium n-propoxide as zirconium source and sucrose as carbon source. Additionally, the effects of water content on micellar size, gelation time, phase composition and size of xerogel carbothermal reduction powder were also discussed in this paper. Meanwhile the carbothermal reduction process of xerogel with water content and C/Zr mole ratio were also studied. The results show that when C/Zr mole ratio is 7 and the volume ratio between acetic acid and water is 5, stable ZrC precursor can be prepared at room temperature, and the Zeta potential is about 18.7mV. The ZrC powder obtained by carbothermal reduction at 1700℃ has an average size of 240nm.