Array substrate and ultrasonic detection device

The invention provides an array substrate and an ultrasonic detection device. The array substrate comprises a substrate, a control circuit and a piezoelectric unit, wherein the control circuit and the piezoelectric unit are located on the substrate; the control circuit includes: a first transistor and a second transistor; the active layer of the first transistor is made of a low-temperature polycrystalline silicon material; the active layer of the second transistor is made of an oxide material; at least one interlayer insulating layer and at least one planarization layer are arranged between the film layer where the grid electrode of the second transistor is located and the film layer where the source drain electrode of the second transistor is located.