The present invention provides an inherent security pool-shell combination low temperature nuclear heating device and an operation program thereof, which belongs to nuclear energy centralized heat-supply field. The invention mainly comprises the following procedures: adopting separated layout, forced circulation and high effective small temperature difference heat exchange in primary loop of reactor; under the precondition that parameter requirements of centralized heat-supply by big cities heat supply network satisfied, reducing work temperature of shell-type heating reactor as far as possible; meanwhile optimized layout of equipment, and organic combination of normal pressure pool in large volume (47) and shell-style heating reactor(29) remove accident possibility of water loss and coldness loss of reactor core (1). Complete inherent safety principle is carried out in the invention. Thus, absolute security of nuclear heating can be guaranteed by using mature pressurized water reactor technology, and enterprises have develop nuclear station pressurized water reactor experience can possibly jump over research and develop stage and enter into nuclear heating market directly, and make a real contribution for energy-saving and emission-reduction and improving country energy structure.