The work aims to research the factors that affect the heat sealing strength of the soft plastic packaging of Johnson oral care products Rembrandt. The effect of the amount of the internal pressure on the heat sealing performance of soft plastic tube was analyzed in the Ansys finite element method. The simulation results showed that when the tube end was 44～54 mm long, the tube body was 65～70 mm long and the tube wall was 0.4～0.5 mm thick, the strain of the soft plastic tube met the requirements of initial conditions; the heat sealing failure of the soft plastic packaging was irrelevant to the density of the materials. With the increase in the elasticity modulus, the maximum strain of the material would gradually decrease. In order to obtain ideal heat sealing (good strength and appearance) and meet the production efficiency, material, structure, temperature, pressure and time, etc. are required to work together.