Heat dissipation model of stacks oxygen-free copper microchannel heat sink was established in this paper. Structural parameters of microchannel heat sink were optimized through theoretical calculations and approximate analysis. Minimum thermal impedance of microchannel heat sink R

thm

=4.205×10

-3

K·cm

2

/W can be obtained when

t

=200μm

ω

c

=60μm

ω

f

=100μm

p=2.2×10

6

Pa. A new kind of five layers oxygen-free copper microchannel heat sink was designed for high power semiconductor laser stacks according to optimized results and influence of hydraulic pressure drop induced by tropism of microchannel. We fabricated the oxygen-free copper microchannel heat sink based on practical technology. The drop of water pressure of 2.02×10

6

Pa is not easy to realize in practice. Thermal impedance of 4.982×10

-3

K·cm

2

/W can fit the need of high power semiconductor laser stacks under the actual drop of operation water pressure.