The invention discloses an autoclaved sand-lime brick prepared from rubber and a preparing method thereof. The autoclaved sand-lime brick is mainly prepared from 0.1-20 parts of rubber powder, 15-30 parts of quite lime and 50-85 parts of sand. The invention further discloses the preparing method of the autoclaved sand-lime brick. According to the autoclaved sand-lime brick and the preparing method, rubber particles are added to replace a part of sand, and therefore the characteristics of an existing autoclaved sand-lime brick are improved in the aspects that as the density of the rubber particles is small, the mass of the autoclaved sand-lime brick can be properly reduced; as the rubber particles have low elastic modulus and high damping, the fragility of the autoclaved sand-lime brick can be effectively reduced, and generation and development of cracks can be reduced; due to adding of the rubber particles, the water absorption speed of the autoclaved sand-lime brick can be increased, and masonry bonding power can be improved; due to adding of the rubber particles, anti-freezing performance can be improved.