A tire pressure sensor device, comprising: a tire pressure sensor comprising a housing, said housing comprising a mounting block, said mounting block comprising a first lateral side, a second lateral side opposite to said first lateral side and a through portion disposed between said first lateral side and said second lateral side, said first lateral side comprising coupling means, said through portion comprising an inlet disposed at one end thereof and located in said second lateral side and an outlet disposed at an opposite end thereof and located in said coupling means; and an air valve comprising an extension rod, said extension rod comprising a rod body and a stop block, said rod body having an outer diameter smaller than the diameter of said through portion, said rod body being inserted through said inlet and said outlet of said through portion for allowing said air valve to be rotated relative to said tire pressure sensor between said an angular position and a second angular position, said stop block being fixedly located at one end of said rod body outside said outlet of said through portion, said stop block being kept in accurate alignment with said through portion for allowing movement of said stop block in and out of said through portion through said outlet when said air valve is in said first angular position, said stop block being kept in a staggered manner relative to said through portion and prohibited from being moved through said outlet of said through portion when said air valve is in said second angular position; characterized in that said coupling means of said first lateral side of said mounting block is a recessed portion inwardly curved in said first lateral side, said recessed portion comprises two retaining grooves disposed at two opposite sides relative to said outlet of said through portion, and said stop block has two opposite ends; and said stop block is abutted at the recessed portion of said mounting block with said two opposite ends positioned respectively in said two retaining grooves when said air valve is in said second angular position. a tire pressure sensor comprising a housing, said housing comprising a mounting block, said mounting block comprising a first lateral side, a second lateral side opposite to said first lateral side and a through portion disposed between said first lateral side and said second lateral side, said first lateral side comprising coupling means, said through portion comprising an inlet disposed at one end thereof and located in said second lateral side and an outlet disposed at an opposite end thereof and located in said coupling means; and an air valve comprising an extension rod, said extension rod comprising a rod body and a stop block, said rod body having an outer diameter smaller than the diameter of said through portion, said rod body being inserted through said inlet and said outlet of said through portion for allowing said air valve to be rotated relative to said tire pressure sensor between said an angular position and a second angular position, said stop block being fixedly located at one end of said rod body outside said outlet of said through portion, said stop block being kept in accurate alignment with said through portion for allowing movement of said stop block in and out of said through portion through said outlet when said air valve is in said first angular position, said stop block being kept in a staggered manner relative to said through portion and prohibited from being moved through said outlet of said through portion when said air valve is in said second angular position; characterized in that said coupling means of said first lateral side of said mounting block is a recessed portion inwardly curved in said first lateral side, said recessed portion comprises two retaining grooves disposed at two opposite sides relative to said outlet of said through portion, and said stop block has two opposite ends; and said stop block is abutted at the recessed portion of said mounting block with said two opposite ends positioned respectively in said two retaining grooves when said air valve is in said second angular position.