The utility model discloses a rotatable type wave breaker for portable tank. The technical problem that solves is that the transmission of the wave breaker that has now the impact force that is unfavorable for receiving the wave breaker is shifted, and the internal surface of jar body can receive mar in various degree and collide the pit. The utility model discloses a pivot, mounting bracket, blade and diaphragm, the mounting bracket cup joint in the pivot, the blade is connected with the mounting bracket joint, the diaphragm sets up with the blade is perpendicular, blade and diaphragm on all be equipped with a plurality of through -hole, the blade be semi -circular structure, is equipped with the draw -in groove in the middle of the blade, the diaphragm passes through the draw -in groove joint on the blade. Adopt behind such technical scheme the utility model discloses the longitudinal impact power and the regurgitate power that make the wave breaker can effectively reduce jar interior liquid reduce the longitudinal impact that the tank head received, and the diaphragm on the wave breaker can reduce transverse impact power simultaneously, guarantees driving safety, improves the life of wave breaker.