A package structure of a soft package lithium battery is provided. Two joining sheets that are correspondingly joined are provided at positions at which peripheries of covering films are press-fit on each tab. Each of the joining sheets has a first press-fit area and a second press-fit area. Joining surfaces of the first press-fit areas of the two joining sheets are correspondingly joined to each other and fixedly sandwich the tab therebetween. The second press-fit area is folded downward away from the tab to the first press-fit area, and the second press-fit areas are press-fit and fixed to the covering films. The concave surface formed by folding between the first press-fit area and the second press-fit area of each of the joining sheets alleviates the problem that hot gases generated during battery discharging exerts an upward force to generate a gap at the press-fit position and lead to electrolyte leakage, thereby prolonging the service life of the battery.