The invention relates to a single crystal furnace with multiple safety protection. The single crystal furnace comprises a lower furnace chamber, a furnace cover, an isolating valve, an auxiliary chamber, an upper transmission mechanism, a water-cooled hot screen installed in the lower furnace chamber, a flow guide cylinder, a flow guide cylinder lifting device, a quartz crucible and a lower transmission mechanism, and further comprises a contact liquid contact system, a weighing system, a CCD monitoring system, and an isolating valve safety monitoring system. The contact liquid contact systemis capable of detecting abnormal operation of an excessive high silicon liquid level and warning. The crucible is automatically descended by the system in a high speed, and the water-cooled hot screenis lifted at the same time, so that a water leakage accident is avoided. The weighing system is capable of uploading and detecting a weight of a pulled silicon rod in real time in a crystal pulling process, when the weight of the silicon rod is suddenly increased or suddenly decreased in an instant moment, the system stops operating, and an alarm is sent. The CCD monitoring system is capable of monitoring abnormal change of a liquid level position in the quartz crucible and warning. The isolating valve safety monitoring system is capable of monitoring a position of the crystal rod, and improving opening-closing safety protection of a valve plate.