Abstract: This paper discusses the collision of fast and slow MHDshocks as well as the interaction between fast or slow shocks and contact surfaces.The main conclusions are as follows.(l) Two fast shocks exchange their places after collision and a contact surface and a pair of slow rarefaction waves occur at the same time.(2)Two slow shocks exchange their places and are both weakened after collision,and a contact surface and a pair of fast shocks occur at the same time.(3)Aforward fast shock and a reverse slow shock exchange their places after collision.The fast shock increases and the slow shock decreases in strength, and a reverse fast shock,a negative contact surface and a forward fast rarefaction wave are formed.(4)Aforward fast shock and a positive(negative)contact surface exchange their places after interaction.Meanwhile, the fast shock diminishes, and a reverse fast rarefaction wave(shock),a reverse slow wave and a forward slow shock are produced.The reverse slow wave is either a shock for small(large)shock angles or a rarefaction wave otherwise.(5)Aforward slow shock and a positive(negative)contact surface exchange their places after interaction. Meanwhile, the slow shock diminishes, and a reverse slow rarefaction wave(shock)and a pair of fast rarefaction waves (shocks)are produced.