Abstract: It is very important to understand the failure mechanism and alternative load paths for the collapse resistance design of a RC specially-shaped-column frame under accidental loading. The collapse tests were carried out for a 1/3-scale 2-story 3multiplied 2-bay reinforced concrete specially-shaped-column space-frame with a sudden side column removal or a sudden corner column removal. Then the test was carried out by a quasi-static load method. The test phenomena, crack distribution, failure process and load-displacement of a specially-shaped-column space frame was studied. The loading process of a specially-shaped-column space frame was analyzed. The transmission process of loading mechanism of the frame was analyzed. The results show that the dynamic effect is not significant to a RC specially-shaped-column frame. There is no pullout reinforcement. The cracks are mainly focus on the vertical member supports. The specially-shaped-column space frame experiences an elastic stage, an elastic-plastic stage, a plastic stage and a catenary stage during a side column test or a corner column test. The catenaries action in a side column is more obvious than that in a corner column. The reinforcement in a slab and a beam is very important to resist the collapse of a specially-shaped-column space frame.