To study the technology of improving the propellant increase burning area based on the principle of manufacturing the special shape objects by the 3D printing technology and the law of propellant burning parallel layers, the integral propellant with high increase burning area having multi empty annular groove tubular structure was designed. The changing rules of area of burning surface and the generation amount of burning gas and generation rate of burning gas for the integral propellant along with burning were analyzed. The calculation method of changing rule of the relative area of burning surface and the relative generation amount of burning gas along with burning were established. The changing rules of the relative area of burning surface and the relative generation amount of burning gas of the integral propellant and 19 holes granular propellant with the relative burning thickness were compared and analyzed. Results show that the designed integral propellant has higher burning area increase. The relative area of burning surface at the end of combustion for the integral propellant used for 155 mm howitzer is 3.1 times more than that of 19 holes granular propellant. The burning gas generation rate of the integral propellant reveals the status of first low and than high in the combustion process. The generation amount of burning gas in the integral propellant combustion after the half is about more than 75.612% of total generation amount of burning gas, 27.575% more than 19 holes granular propellant.