A carbon intensity accounting method was developed to account for the distinct data characteristics of inland river ship based on carrying capacity and transport distance. The correlation between ship carbon intensity indicator (CII) and factors including vessel age, ship type, port of registry and average speed was analyzed based on operational data collected from ships of 5,000GT and above registered in Chongqing after static parameter filling and dynamic trajectory repair. The results indicated that the carbon intensity values of the study sample in October 2021 were all on the order of 10^-6, ranging between 2.47×10^-6 and 10.53×10^-6t/(t·km). As vessel age increases, the CII demonstrates an upward trend, whereas carbon emissions exhibit a negative correlation with carrying capacity. The overall energy efficiency levels of different ship types were quantified and ranked based on the median and mean values of their CIIs. The resulting order from highest to lowest energy efficiency was Ro-Ro vessels, general cargo ships, container ships, dry bulk carriers, and passenger ships. Vessels registered in main urban area of Chongqing generally demonstrate superior energy efficiency compared to those from its outer districts and counties. Thus establishing a standardized carbon emission monitoring system was crucial to enhance the overall energy efficiency of the ship fleet registered in Chongqing. The CII demonstrated a strong correlation with ship average speed. Furthermore, different ship types exhibit distinct variation characteristics, each reaching its minimum carbon intensity at different specific speed points.