A comprehensive comparison between water and different mass fractions of glycerol-water (40, 50, and 60 wt %) was performed to study the breakup characteristics in free opposed impinging jets. The effect of viscosity and jet velocity on liquid sheet breakup mode, liquid sheet diameter, droplet size, and velocity was investigated qualitatively via particle image velocimetry technology. The results show that as the jet velocity increases, the evolution of breakup mode presents closed-rim mode, openrim mode, rimless mode, wave or ligament mode, and fully developed mode successively for water, 40 wt % glycerol-water, and 50 wt % glycerol-water, but only the first four breakup modes are observed for 60 wt % glycerol-water. The liquid sheet of water more easily breaks up into tiny droplets. However, higher impingement momentum and jet velocity are required for 60 wt % glycerol-water opposing collision to reach the same breakup mode, which is due to the high viscosity restraining of liquid sheet breakup mode. D-32 decreases sharply at the closed-rim mode and open-rim mode. With the increase in jet velocity, variation of D-32 is insensitive at a fully developed mode between these four fluids, and the minimum value of D-32 reaches around 200 pm. D-32 decreases with moving down along the Y-axis from -20 to -40 mm. As the jet velocity increases, droplet size distribution becomes narrow and the number of droplets significantly increases, with the droplet size tending to be more uniform with a smaller diameter. The experimental results indicate that viscosity plays a crucial role in constraining the evolution of liquid sheet breakup mode at a low jet velocity for the closed-rim mode and open-rim mode. However, a high turbulence degree is more important to promote liquid sheet and droplet breakup at a high jet velocity, which is corresponding to the wave or ligament mode and fully developed mode.