The invention provides an obstacle crossing device of a self-walking type aerial work platform. The obstacle crossing device comprises two end plates, a middle plate and two connecting rotating shafts. The two end plates are of same structures; main bodies of the end plates are triangular plate bodies, and raised grains are arranged on the end plates; the middle plate is integrally composed of a main plate body, a connecting lug and a flange; a groove is formed in the upper end face of the main plate body, and a flange matched with the groove is arranged on the lower end face of the main plate body; the front end face and the rear end face of the main plate body are each provided with a side edge groove; and two end plates are movably arranged on the two sides of the middle plate through the two connecting rotating shafts. The self-walking type obstacle crossing device is simple in structure, easy to carry, rapid and convenient to set up, safe and reliable in use and capable of effectively improving the obstacle crossing capacity of the self-walking type aerial work platform