The invention provides a piston test apparatus. The piston test apparatus comprises a platform base, a platform support, a piston connecting rod, a cylinder sleeve, a cooling unit and a heat engine coupling unit. The piston connecting rod and the cylinder sleeve are installed on the platform base; the heat engine coupling unit is installed on the platform support for providing a periodical high-temperature high-voltage environment for a test; a piston to be tested is connected with the cylinder connecting rod through a piston pin and is installed in the cylinder sleeve; and the heat engine coupling unit, the cylinder sleeve and the piston form a sealing space. According to the invention, periodical pressure and continuous high temperature are provided through the heat engine coupling unit, the high-temperature high-voltage environment generated through deflagration of mixed gas in an engine combustion chamber can be simulated, the main stress condition of the piston, i.e., the mechanical stress and thermal stress bearing condition of the top portion of the piston is tested, and piston heat engine coupling testing is quite conveniently realized.