With the rapid development of wireless local area network(WLAN) technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model(HMM), is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm,the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort. With the rapid development of wireless local area network (WLAN) technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal timing-varying. A novel fingerprint positioning algorithm, known as the adaptive The radio map with updated method based on hidden traces model (HMM), is proposed by the collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to This method is a combination of machine learning, information gain theory and fingerprinting. The collected data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort .