In order to develop a kind of polyurethane coatings with high permeability andcollapse resistance for porous wood，a alkyd resin with high hydroxyl value of 168 mgKOH/g was synthesized，and the polyethylene micro-wax powder with refractive index similar to thatof alkyd resin was combined with TDI-TMP and TDI curing agents to prepare the polyurethanecoatings. The effect of different hydroxyl value，ratio of isocyanate group to hydroxyl group［n（— NCO）∶n（— OH）］ on coating collapse resistance and different filling powder selectionand addition amount on coating were investigated. The results showed that the hardness andsolvent swelling resistance of the film increased gradually with the hydroxyl value increasingfrom 105 mgKOH/g to 168 mgKOH/g. When the n（—NCO）∶ n（—OH） increased from 0. 6∶1 to 1. 4∶1，the hardness and solvent swelling resistance of the coating increased linearly.The use of micro wax powder instead of conventional talc powder and transparent powder， improved the filling and good light penetration. After testing and application，it had been proved that the film transparency of the polyurethane coatings was good，no odor drying at normal temperature for 24 hours，basically no collapse after two weeks. It owned short dryingtime，and granular effect. The coatings had good filling property and high permeability，and could be applied to African porous wood to improve the utilization rate and qualityrequirements of African wood.