An engine temperature regulating device, installed in a casing with a cooled air inlet, comprising: a power source; a link rod module, connected to the power source; a control module, for detecting a temperature for starting the engine to obtain a temperature signal, and controlling the drive of the power source when the temperature signal is lower than a predetermined value or controlling and turning off the power source when the temperature signal achieves the predetermined value; and a fan cover module, covered onto the cooled air inlet, and further comprising: a fixed casing, formed by mounting a first surrounding member around a first sidewall, and the first sidewall having a plurality of first air intake holes and a plurality of first shelter plates arranged alternately with one another, and disposed at a plurality of first ventilation holes of the first surrounding member, and at least one fixed block disposed around the external periphery of the first surrounding member and capable of locking the casing with the cooled air inlet; and a movable casing, formed by mounting a second surrounding member around a second sidewall, and the second sidewall having a plurality of second air intake holes and a plurality of second shelter plates arranged alternately with one another, the second surrounding member having a plurality of second ventilation holes, and a positioning block disposed around the external periphery of the second surrounding member, and the link rod module being coupled to the movable casing, and the power source controlling the link rod module to rotate the movable casing, so as to adjust the first air intake holes and the first ventilation holes of the fixed casing to a smooth or obscured state, and when the first air intake holes are situated at the obscured state, the first ventilation holes still maintain holes. a power source; a link rod module, connected to the power source; a control module, for detecting a temperature for starting the engine to obtain a temperature signal, and controlling the drive of the power source when the temperature signal is lower than a predetermined value or controlling and turning off the power source when the temperature signal achieves the predetermined value; and a fan cover module, covered onto the cooled air inlet, and further comprising: a fixed casing, formed by mounting a first surrounding member around a first sidewall, and the first sidewall having a plurality of first air intake holes and a plurality of first shelter plates arranged alternately with one another, and disposed at a plurality of first ventilation holes of the first surrounding member, and at least one fixed block disposed around the external periphery of the first surrounding member and capable of locking the casing with the cooled air inlet; and a movable casing, formed by mounting a second surrounding member around a second sidewall, and the second sidewall having a plurality of second air intake holes and a plurality of second shelter plates arranged alternately with one another, the second surrounding member having a plurality of second ventilation holes, and a positioning block disposed around the external periphery of the second surrounding member, and the link rod module being coupled to the movable casing, and the power source controlling the link rod module to rotate the movable casing, so as to adjust the first air intake holes and the first ventilation holes of the fixed casing to a smooth or obscured state, and when the first air intake holes are situated at the obscured state, the first ventilation holes still maintain holes. a fixed casing, formed by mounting a first surrounding member around a first sidewall, and the first sidewall having a plurality of first air intake holes and a plurality of first shelter plates arranged alternately with one another, and disposed at a plurality of first ventilation holes of the first surrounding member, and at least one fixed block disposed around the external periphery of the first surrounding member and capable of locking the casing with the cooled air inlet; and a movable casing, formed by mounting a second surrounding member around a second sidewall, and the second sidewall having a plurality of second air intake holes and a plurality of second shelter plates arranged alternately with one another, the second surrounding member having a plurality of second ventilation holes, and a positioning block disposed around the external periphery of the second surrounding member, and the link rod module being coupled to the movable casing, and the power source controlling the link rod module to rotate the movable casing, so as to adjust the first air intake holes and the first ventilation holes of the fixed casing to a smooth or obscured state, and when the first air intake holes are situated at the obscured state, the first ventilation holes still maintain holes.