A connecting structure of a sliding door and a swing door for a vehicle includes a front door swingably, and a rear door slidably installed; a first vertical beam vertically installed at the front door of the vehicle body and including upper and lower latch reinforcements which are horizontally installed at the upper and lower portions thereof, respectively; a second vertical beam vertically installed at the rear door of the vehicle body and including an upper and lower roller arm reinforcements which are horizontally installed at the upper and lower portions thereof, respectively; and a female and male pole brackets formed at rear and front sides of the front and rear doors, respectively. It is possible to improve safety by ensuring a side strength of the vehicle and increase marketable quality by reinforcing the connecting structure of the sliding door and the swing door at the same time.