The invention provides a self-leveling polymer cement base repair mortar which is used for repairing cracks of a concrete building. The self-leveling polymer cement base repair mortar comprises the following components in part by weight: 25 to 60 parts of cement, 40 to 70 parts of sand, 1 to 5 parts of redispersible rubber powder, 0.2 to 1.0 part of interface reinforcing agent, 0.1 to 0.5 part of water-retaining agent, and 0.1 to 1 part of water reducing agent; the self-leveling polymer cement base repair mortar has high self-leveling performance; after the building is repaired by the mortar, the whole flatness is high, surface finishment is uniform, and the decoration performance is high; the mortar has high crack infiltration capacity, can infiltrate the crack with the length of less than 1mm, has high bonding strength between the mortar and the original concrete, and does not fall off after being dried and hardened; and after being hardened, the mortar has micro expansion performance, and can compensate the partial shrinkage of concrete, improve the impermeability of the concrete, and is suitable for crack repairing of the concrete.