An imaging lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens sequentially arranged from a magnifying side to a narrowing side. The second lens and the third lens constitute a first composite lens, the fourth lens and the fifth lens constitute a second composite lens, and the sixth lens and the seventh lens constitute a third composite lens. The imaging lens has the advantages of small size and good imaging quality.