Blazars exhibit rapid variability in both luminosity and polarization at all wavebands (Angle & Stockman 1980). The optical variability of blazars is relevant to physical condition in the deep interiors of the objects and general constraints on the emission mechanism can be derived from the characteristics of variations (Wallinder et al. 1992). A program to investigate the optical variability in blazars, utilizing modern CCD detectors, has been undertaken by us since 1987. Preliminary results have been reported by Guibin et al. (1995). Now, the results of a fast photometry monitoring for 8 blazars, PKS 0422+004, PKS 0754+101, B2 1156+295, 3C 334, OT 081, PKS 2254+074, PHL 658 and PKS 2128-123, are presented. Variability on time scales significantly less than a day was observed for PKS 0422+004, PKS 0754+101, B2 1156+295, OT 081 and PKS 2254+074.