We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube (PMT) with precise temperature control, which can capture fast single photons with intervals around 10 ns. By improvement of the electromagnetic shielding and introduction of the self-differencing method, the dark counts (DCs) are cut down to ～1%. We further develop an ultra-stable PMT cooling subsystem and observe that the DC goes down by a factor of 3.9 each time the temperature drops 10°C. At 20°C it is reduced 400 times with respect to the room temperature (25°C), that is, it becomes only 2 counts per second, which is on par with the superconducting nanowire detectors. Meanwhile, despite a 50% loss, the detection efficiency is still 13%. Our detector is available for ultra-precise single-photon detection in environments with strong electromagnetic disturbances.