This paper presents a novel mobile wearable context-aware indoor maps and navigation system with obstacle avoidance for the blind. The system includes an indoor map editor and an App on Tango devices with multiple modules. The indoor map editor parses spatial semantic information from a building architectural model, and represents it as a high-level semantic map to support context awareness. An obstacle avoidance module detects objects in front using a depth sensor. Based on the ego-motion tracking within the Tango, localization alignment on the semantic map, and obstacle detection, the system automatically generates a safe path to a desired destination. A speech-audio interface delivers user input, guidance and alert cues in real-time using a priority-based mechanism to reduce the user’s cognitive load. Field tests involving blindfolded and blind subjects demonstrate that the proposed prototype performs context-aware and safety indoor assistive navigation effectively.