1, categories are different. Lettuce is a general term; and Romaine lettuce is only a kind of lettuce. 2, different taste. Lettuce tastes very crispy, and contains a lot of water; Romaine lettuce taste a little worse, and there is not much water, not like ordinary lettuce as crispy. 3, eat different. Lettuce can not only be eaten cold, but also can be fried, stewed soup or cooked noodles to eat, eating more diverse; Romaine lettuce is generally only used for cold food, there is no other way to eat. 4, belongs to a different subject. Lettuce is the chrysanthemum family of plants, is an annual or biennial herb, it is the leaf lettuce is commonly known, leaf long obovate, dense into a kale-like leaf ball, can be eaten raw, crisp and refreshing, taste sweet, lettuce is native to the Mediterranean coast of Europe, the earliest is the Ancient Greeks and the Romans to eat, imported into China has a long history of southeastern coastal planting more. Romaine lettuce is similar to the Chinese knot lettuce, just in the texture, not as refreshing as the knot lettuce, its eating method is also very similar to the knot lettuce, can be directly washed and mixed food.