Abstract: A flexible container has a bag body and a sealing portion at the upper end of the bag body's sidewalls. The sealing portion includes a strip and a groove which are relatively arranged on the inner side of the sealing portion. The strip has a convex mushroom-shaped cross-section, and the groove has a concave mushroom-shaped cross-section. The strip and groove interlock by an interference snap fit connection. The ends of the strip and groove transition from the mushroom-shaped cross-section to a rectangular-shaped cross-section which also snap fit together. The mushroom-shaped cross-section in the middle portion of the strip and groove create a sealing portion that is easy to seal and difficult to open. To help open the sealing portion, tabs extend up from the bag body's sidewalls. There is a cross-sectional transition design near the end, and the transitional shape can increase the sealing force to optimize the anti-leak effect.