Provided are an array substrate, a touch display panel and a method for calculating touch pressure. The array substrate includes: a display region with a non-display region around the display region, thin film transistors in the display region and having an active layer, at least two semiconductor pressure sensors, a bias voltage applying circuit for applying a bias voltage to each semiconductor pressure sensor, and a voltage detecting circuit for acquiring a strain voltage from each semiconductor pressure sensor. A first straight line connecting a first connecting terminal and a second connecting terminal of the semiconductor pressure sensor intersects a second straight line connecting a third connecting terminal and a fourth connecting terminal of the semiconductor pressure sensor. The semiconductor pressure sensor is a semiconductor film in a polygonal structure having at least four sides, the active layer and the semiconductor film are in a same layer.