The invention discloses a closing type automatic flashing point testing system. The closing type automatic flashing point testing system comprises a testing cup, a temperature control mechanism, a motor, a shell and a guide mechanism, wherein the detection cup is internally provided with a separation plate in a clamping manner and the separation plate is used for equally dividing the detection cupinto an oil storage cavity and a cavity; a top plate is formed on the top surface of the cavity; the temperature control mechanism comprises a heating shell body and a cooling shell body; the top endof the cooling shell body is fixedly connected with a cover plate; the top end of a shaft body of the motor rotatably penetrates through the bottom surface of the temperature control mechanism in a sealed manner and is fixedly connected to the center of the bottom surface of the detection cup; the shell sleeves the peripheries of the detection cup, the temperature control mechanism and the motor;a ventilation hole is formed in the top end of the shell; the guide mechanism comprises an arc-shaped retractable plate and a rectangular retractable plate; each of the arc-shaped retractable plate and the rectangular retractable plate comprises an upper sleeve, a middle sleeve and a lower sleeve. When detection is finished, the upper end of a heating cavity is rapidly and rotatably sealed, so that a condition that surplus liquid steam to be detected enters air is prevented; temperature rising and temperature reduction are rapidly controlled and the problem that the steam enters the shell sothat the steam is dispersed too rapidly at an early period and the gathering problem at a later period are effectively avoided; the repeatability and reproducibility of detection are improved.