The unsteady convective heat transfer performances of molten salt in receiver tube were experimentally investigated.When the heat flux or molten salt flow rate varied，the unsteady convective heat transfer appeared.During the unsteady process，the molten salt outlet temperature varied slower than the wall temperature，but their variation trends were similar.For lower inlet temperature，the viscosity of molten salt was higher，and the heat transfer process varied slower.For larger heat flux variation，the temperature varied more quickly，but the unsteady duration changed very little.The unsteady convective heat transfer process was remarkably affected by molten salt flow rate，and it can be significantly accelerated by flow rate rising.In addition，the unsteady heat transfer performances of the receiver tube with insulation layer were similar to those without insulation layer，but the wall temperature was higher.