Waterway transportation is an important mode of transportation in modern society. Especially after the Silk Road, waterway transportation plays an important role in global trade transportation. However, with the expanding use of ships, ships hit the reef, illegal transportation, marine pollution and other waterway traffic accidents occur frequently. As unique identities, Ship Identification Characters(SICs) have been playing a significant role in ship traffic behavior control. In order to realize the intelligent detection of ship identification characters, this paper proposes an improved TextBoxes detection method for efficient and automatic detection of ship identification characters. Experiments show that this improved algorithm improves the detection accuracy by about 6% compared to TextBoxes themselves.