A portable multi-purpose safety triangle includes: a tripod including: a sign unit; and a support unit which supports the sign unit and is configured to be selectively set in one of a folded state and an unfolded state; and a frame including: a frame body having an accommodation space for accommodating the tripod therein; and a frame cap selectively coupled to the frame body. The support unit includes: a first assistant support and a second assistant support that support the sign unit; an elastic member whose both ends are respectively connected to the first assistant support and the second assistant support, the elastic member providing a restoring force to the first assistant support and the second assistant support; and a main support that supports the elastic member. The sign unit includes a flexible material such that the size thereof is changed according to the state of the support unit.