An industrial computer hinge assembly includes a bolt having a head and an extension, a first positioning ring with a first hook, a second positioning ring with a second hook, multiple leaf springs and an assembly device having an extension hole and a first fixing hole defined in a main board casing to correspond to the extension of the bolt and the first hook respectively and a hole and a second fixing hole defined in a screen casing to correspond to the extension and the second hook respectively. After the extension combines with the nut, engagement between the first positioning ring and the second positioning ring provides friction force to support the screen casing relative to the main board casing.