A paper feeding device includes a cover, a base, a pickup roller assembly and at least one paper blocking unit. The paper blocking unit is placed beside the pickup roller assembly, has a paper blocking element and a projection projecting from the upper portion of the side wall of the pickup roller assembly. The paper blocking element includes a connecting portion, a paper blocking arm, a pivot rotatablely connecting the cover. A connecting arm extends upwards from the end of the pivot, a blocking portion projects from the outer side of the connecting arm, a passage is formed between the blocking portion and the connecting arm. The projection can be downward against the blocking portion of the paper blocking element or pass through the passage of the paper blocking element to allow the paper to be fed in, so the cooperation is easy, the paper feeding device works smoothly.