A hinge assembly includes a pivot shaft, a fixing module, a rotatable module, and a fixing member. The pivot shaft includes a first end and a second end opposite to the first end. The fixing module is non-rotatably sleeved on the pivot shaft adjacent to the first end and includes a first magnet. The rotatable module is rotatably sleeved on the pivot shaft adjacent to the second end and includes a second magnet. A polarity of the second magnet faces an opposite polarity of the first magnet such that the first and second magnets creating an attracting force. The rotatable module is pushed to tightly contact the fixing module by the attracting force such that a friction is created between the rotatable module and the fixing module to hold the rotatable module. The fixing member is fixed at the second end of the pivot shaft.