To prevent the inland river navigation ships exceed the specified draft limits，a real-time active detection of dynamic ship draft is necessary.We propose an inland river ships draft detection system based on multi-beam echo sounder.Based on sonar ranging technology，and design the framework of detection system，the software architecture and the communication protocols of multi-beam echo sounder system.Data filtering is adopted to remove abnormal data.As a result，the system displays clear and accurate ship draft outlines，real-time ship draft.The feasibility for inland river ships draft monitor and control is verified.