This article considers estimating the intensity of nonhomogeneous earthquake data, which can be modeled by a nonhomogeneous Poisson process. We use the local maximum likelihood method proposed by Cheng (2006) to estimate the intensity function. We compare our method with parametric MLE method through simulation. In addition, for examining each of the estimation method, we use a diagnosis tool of residual process proposed by Ogata (1984). With the local maximum likelihood estimator, we nvestigate the intensity of the aftershock sequence triggered by Chi-Chi earthquake, which occurred in Taiwan in 1999.