This invention relates to a double- cycle high efficient heat pipe heat exchanging system that can control the heat exchanging quantity. There are evaporator and condenser two types of heat exchangers. The number of each type is one or several that formed by connected in parallel. This system includes: condensate supplying and distributing system; gas-liquid two phases flowing and separating system; gaseous phase transmitting and distributing system, liquid phase collecting and storing system; heat exchanging quantity controlling system. The evaporator of heat pipe, condenser, gas-liquid separator, liquid storage, solution circulating pump, liquid distributor, the connecting pipeline and related controlling parts are connected together to form the double cycles controllable heat pipe system. The solution pump, liquid distributor, evaporator and gas-liquid separator are connected together to form independent working fluid cycle, which settle the problems that working fluid carrying capacity is not enough and liquid distribution is uneven.