Aiming at laser disturbance to IR homing anti-ship missile, laser disturbance to IR detector was researched. First, link model on laser disturbance to anti-ship missile IR detector was set up. Then laser atmospheric transmittance on the sea was deduced. 1.06μm laser atmospheric transmittance on the sea was calculated. The relationship was obtained among atmospheric transmittance and visibility and elevation. And then 10.6μm laser atmospheric transmittance curve was described. The curve is changed by visibility and propagation distance. Finally, 1.06μm laser was given as an example, the necessary laser energy which can disturb effectively anti-ship missile IR detector was calculated.