By taking printing service as the object of study, carbon footprint was assessed with the establishment of carbon footprint evaluation model for printing service, upon which a carbon emission calculator was developed. After field research in four typical book printing enterprises, the carbon footprint evaluation data collection program was improved with the acquisition of actual primary data and secondary data of carbon emission factors, covering the stages of prepress, printing, and post-press finishing, which laid the foundation for the development of carbon emission calculator. The printing service carbon footprint assessment method based on lifecycle could be a good method to determine the source of the printing carbon emissions. More than 60 printing enterprises’ trial results indicated 83% degree of satisfaction for the carbon calculator with 30% energy saving and emission reduction, 3.6% reduction in management costs, and average 2.5% increase in corporate profits. The results showed that the research and development of the calculator could well reflect the carbon emission level in printing service, thus guide the carbon emission reduction, and provide more accurate calculation method for clients when it comes to comparing the products and services.