A foldable stroller frame with an auto-extending wheel distance adjustment is provided with at least a front support rack, a rear support rack, a pushing rack and a pair of power transmitting rods. A pair of first sliding-and-pivoting connectors is mounted for moving along the front support rack and permitting the pair of rear wheel sets capable of moving toward the front wheel set for shortening the wheel distance between the pair of rear wheel sets and the front wheel set. The pushing rack has an upper pushing section and a lower pushing section pivoted to the lower portion of the upper pushing section. The pair of power transmitting rods is connected between the rear support rack and the pushing rack for driving the rear support rack by rotating the pushing rack.