Abstract: By analyzing strong ground motion records obtained from the 2008 Wenchuan MS8.0 earthquake, a ground motion acceleration parameter, named Maximum Critical Acceleration (MCA), is given in this paper. Analyzed result shows that the parameter MCA is more relevant to earthquake-induced landslide than PGA, and by using it we may solve the problems encountered in using PGA criterion to judge whether landslide can be triggered during earthquake. The MCA attenuation relation is built based on the data from the Wenchuan earthquake in Longmenshan mountain area. The appraised landslide area following the attenuation relation well fits the actual landslide distribution in the Wenchuan earthquake-hit area, indicating that this parameter is suitable for evaluating earthquake-induced landslide. Comparing MCA directly with slope critical acceleration may determine whether landslides can be triggered or not, simplifying the judging process of earthquake-induced landslide. The conclusion is that this parameter can be applied to the earthquake-induced landslides evaluation as an earthquake triggering factor.