The invention relates to a preparation method of a microchannel heat sink for high-heat flux heat dissipation. The method includes the following steps that: a) materials are selected; b) a microchannel is made inside a plate; c) three-dimensional microchannel deformation-free modeling is performed; d ) and a metal frame, a ceramic frame, an outer lead, an IC device, a sensor and a heater are integrated on an active microchannel heat sink, so that system miniaturization can be realized, mechanical support and environmental protection are provided for a chip and an internal circuit, and an input and output function is realized for the chip and the internal circuit. The thermal expansion coefficient of the product is adjustable; and heat generated by devices or a system can be taken away from the heat sink through a high-thermal conductivity medium, the temperature of the surface of the heat sink can be decreased as much as possible and remain constant. The microchannel heat sink has the advantages of small size, large heat dissipation area, good solderability and high stability, and can meet the requirement of high-power density heat dissipation, and can be in sealed connection with other components or parts.