Car body assembling tool and car body assembling method

The invention discloses a vehicle body assembling tool and a vehicle body assembling method.The vehicle body assembling tool comprises an underframe clamping device, an in-vehicle pressing device, a side wall clamping device, a vehicle roof clamping device and an end wall clamping device, and the underframe clamping device firstly limits the position of a supported underframe and fixes the underframe; the chassis is pressed and fixed on the chassis clamping device by the in-vehicle pressing device; the side wall clamping device is fixedly connected with the side wall and adjusts the position of the side wall relative to the bottom frame till a lower edge beam of the side wall is tightly pressed and attached to the bottom frame. The car roof clamping device is connected with the supported car roof and limits the position of the car roof relative to the underframe and the side wall until the car roof falls on an upper edge beam of the side wall; the end wall clamping device is connected between the underframe c