A tyre pressure gauge, comprising a casing (1) provided with an air inlet hole (4), and a valve assembly (2) and a nut post (3) connected to the casing (1). The valve assembly (2) comprises a nozzle rod (20), a first screw rod portion (21) and a second screw rod portion (22) which are arranged sequentially, and a nut (23) sleeved on the first screw rod portion (21). The nut post (3) comprises an insertion portion (31) and a limiting portion (32). A stepped hole (109) penetrating the top and bottom of the casing (1) and matching the nut post (3) is arranged on the casing (1), the insertion portion (31) of the nut post (3) passes through the stepped hole (109) and is connected to the second screw rod portion (22) of the valve assembly (2), and the limiting portion (32) of the nut post (3) abuts against the casing (1). The connection structure between the tyre pressure gauge and a rim is firmer and not prone to being affected by a centrifugal force produced by the casing when a tyre rotates, which causes the cas
