Feature-based mobile robot simultaneous localization and mapping (SLAM) is an open problem in the field of robotics. This paper summarizes the current research on SLAM in three aspects: feature extraction,methods and data association. An overview of mobile robot localization is given,with an emphasis on the main problems of SLAM and solutions to them. Meanwhile,feature extraction in an indoor environment and the principles of data association are discussed. Finally, future trend in this field is pointed out.