A touch substrate, a method for forming the same and a touch display device are provided. The touch substrate includes: a primary touch region, a secondary touch region, a peripheral region, primary touch electrodes at the primary touch region, secondary touch electrodes at the secondary touch region, a plurality of bonding terminals, a plurality of primary touch signal channels and a plurality of secondary touch signal channels configured to transmit touch signals to the secondary touch electrodes at the peripheral region, where each bonding terminal is coupled to a corresponding primary touch electrode via a signal transmission line, and configured to provide the primary touch signal channel to transmit the touch signal to the corresponding primary touch electrode, where at least a part of the primary touch signal channels is reused as the secondary touch signal channels.