It depicts a young Jesus with the Virgin Mary and Saint Joseph (the three of whom make up the Holy Family, the earthly trinity of the painting's title), together with God the Father and the Holy Spirit (who with Christ as God the Son form the Holy Trinity).

The Holy Trinity painting is notable for its ideas taken from ancient Roman arches and stringent compliance to newly invented point of view methods, with a vanishing point at the audience’s eye height, so that, as Vasari characterizes it, “a vault stretched in perspective, and split into squares with rosettes that reduce and are stylized so well that there appears to be a hole in the wall.”

The Trinity is noteworthy for its inspiration taken from ancient Roman triumphal arches and the strict adherence to recently developed perspective techniques, with a vanishing point at the viewer's eye level, so that, as Vasari describes it "a barrel vault drawn in perspective, and divided into squares with rosettes that diminish and are foreshortened so well that there seems to be a hole in the wall."