A foldable parking rack for a bicycle includes a base and a limiting device. The base has a wheel receiving frame having two elongated limiting members and two abutting members concaved with two abutting recesses respectively. An accommodating space is formed between the two elongated limiting members and between the two abutting members. The limiting device has a swinging bar, a spring, and two limiting cones installed at an end of the swinging bar in a way that peaks of the two limiting cones are pointed towards each other. When the swinging bar is swung about a pivot, a body of the swinging bar is swung correspondingly to the accommodating space and the two abutting recesses in a way that the juncture of the peaks of the two limiting cones corresponds to the accommodating space and the two abutting recesses.