In multiobjective evolutionary algorithms, most selection operators are based on the objective values or the approximated objective values. It is arguable that the selection in evolutionary algorithms is a classification problem in nature, i.e., selection equals to classifying the selected solutions into one class and the unselected ones into another class. Following this idea, we propose a classification based preselection for multiobjective evolutionary algorithms. This approach maintains two external populations: one is a positive data set which contains a set of 'good' solutions, and the other is a negative data set contains a set of 'bad' solutions. In each generation, the two external populations are used to train a classifier firstly, then the classifier is applied to filter the newly generated candidate solutions and only the ones labeled as positive are kept as the offspring solutions. The proposed preselection is integrated into the Pareto domination based algorithm framework in this paper. A systematic empirical study on the influence of different classifiers and different reproduction operators has been done. The experimental results indicate that the classification based preselection can improve the performance of Pareto domination based multiobjective evolutionary algorithms.