This paper presents a new supercritical carbon dioxide (SCO2) cannon based on the carbon dioxide(CO2)'s thermodynamic cycle under constant volume.First,Virial equation and NIST database are applied to formulate SCO2's property and analyze the thermodynamic cycle,which is aimed to get the optimization equation using the cannon's exit velocity as objective function.Then the cannon's structural parameters,such as diaphragm thickness and barrel length,and CO2's filling mass,are optimized.Finally,the flow field and velocity's change during the launch process is performed with FLUENT.In field test,the ultra-high pressure sensor and ultra-high speed camera are used to measure the pressure distribution along the barrel's axial direction and the projectile's exit velocity under different conditions.The results show that all the performance indexes meet the design requirement.The innovative SCO2 cannon in this paper has obvious advantages such as high safety,low cost and fast loading,which can be applied in many situations such as disaster relief,peacekeeping and anti-terrorism.Moreover,the unique energy storage method and thermodynamic design ensure its subsequent development.