A polarizer (2) for a liquid crystal display device includes a polarizer base (21), a first protective layer (20) and a second protective layer (22) on two sides of the polarizer base for protecting the polarizer base, and an anti-reflection layer (25) on the first protective layer. The anti-reflection layer includes a first layer (26), a second layer (27), a third layer (28) and a fourth layer (29) stacked in order. The anti-reflection layer of the polarizer can reduce the reflection of the light irradiated on the polarizer, and the loss of light can be reduced and higher light transmission rate can be achieved.