Reinforced concrete shear walls are the primary lateral-load carrying elements in the high-buildings. Its stiffness property has significant influence on the internal force distribution of structures. Reinforced concrete shear walls were set up by MSC.Marc and validated by comparing with lots of test data. A parametric study was conducted on reinforced concrete shear wall to study effective stiffness influenced by the shear-span-to-wall-length ratio, axial compression ratio, yield strength of longitudinal bars in wall boundaries, longitudinal reinforcement content in wall boundaries and concrete strength. The results show that axial compression ratio is the main factor. A simplified formula to evaluate the effective stiffness of reinforced concrete shear wall was proposed on the basis of the parametric study. The results obtained from the simplified formula is in good agreement with those from experiments. It proves that the simplified formula is reasonable and reliable and can be used for reference.