Amplitude versus Angle (AVA) attributes include information about rock properties. Using a dataset from South America, we performed a multiple realization method to get multiple equal-probable AVA intercepts, gradients, and their products. We generated a 3-D histogram to evaluate the variability of those AVA attributes. In the same area, we chose a 2-D section by matching it to three wells. Then we calculated the shale volume along these three wells and found the well with low shale volume has high AVA uncertainty, which made us guess the low shale/sand ratio may cause high AVA uncertainty. The further work need to be done is to use more real data to exam our conjecture, namely, whether there exist an empirical relationship between AVA uncertainty and rock information, such as shale volume, impedance or velocity.