The deepwater swimming-pool type nuclear reactor for supplying heat relates to heating technology using nuclear energy under lower temperature. The invention provides a deepwater swimming-pool type nuclear reactor for supplying heat, having the advantage of a swimming-pool type reactor, which is of simpler in structure, higher inherent safety and small scale economically. The parameter of supplying heat can also be raised to make the temperature of water inlet in the heating net responsed to the requirement of the middle or small heating net. The method adopted is to deepen the depth of pool water being resulted in high hydrostatics at the reactor core under the bottom of pool water. The heat exchanger is thus inverted so that the temperature of the first heat exchange outlet is raised. The invention is good in its simple structure. It can be comprehensively utilized to increase economic returns.