The invention discloses a low-power dissipation RS latch unit and a low-power dissipation master-slave D flip-flop, which is characterized in that the low-power dissipation RS latch unit comprises an input driving and synchronizing circuit, a pull-down circuit, a function control circuit, a first phase inverter and a second phase inverter, wherein the first phase inverter and the second phase inverter are mutually overlapped and coupled. The low power dissipation master-slave D flip-flop is composed of an input phase inverter, a clock phase inverter, a first low-power dissipation RS latch unit and a second low-power dissipation RS latch unit, wherein the first low power dissipation RS latch unit and the second low power dissipation RS latch unit have the same inner structure and are cascaded. The low power dissipation master-slave D flip-flop has the advantages that the low-power dissipation RS latch units use three kinds of leaked power consumption lowering technology, i.e. P-type logic technology, function control technology and double-threshold technology, so that the low-power dissipation RS latch units have better leaked power consumption inhibiting performance. The low-power dissipation master-slave D flip-flop has simple and totally symmetrical circuit structure. Compared with the traditional single-threshold transmission gate D trigger circuit, the invention can save 80% of leaked power consumption and 40% of total power consumption in the 90 nm process, so that the invention is suitable to serve as a digital circuit unit to the design of low-power consumption integrated circuits in the deep sub-micron CMOS process.