Aiming at the poor flexibility of Automated Guided Vehicle (AGV) localization method in industrial working field, an Ultra WideBand (UWB) indoor localization system by using DW1000 Radio Frequency (RF) chip was designed and implemented. Firstly, to solve the problem of conflicts and networking of tags, the efficient mechanisms for multi-station ranging and multi-tag scheduling were proposed. Secondly, concerning the low accuracy and poor stability of the triangle centroid localization algorithm caused by maximal ranging errors, a concept of credibility was introduced and the inner triangle centroid algorithm was proposed, which could weaken the influence of maximal ranging errors through credibility coefficient to improve the algorithm performance. Finally, the proposed system was applied to the industrial workshop with 20 tags. For a single tag, the average frequency of coordinate updating reached 24 Hz and its standard deviation was 3 Hz; the static average localization error was 11.7 cm and its standard deviation was 2.5 cm; the dynamic maximum error was within 30 cm. The experimental results show that the proposed localization system has the characteristics of high real-time performance, high precision and high stability.