Abstract: A chair structure has assembly portions provided on its seat for assembling with upper ends of chair legs. Button holes and a latch block are respectively provided on each chair leg and the seat for correspondingly snap fit together. Additionally, mortise holes and tenons are also provided respectively on the seat and the chair legs so that they can joint firmly together after the assembly of the seat and the chair legs. Thus, in addition to the engagement between the latch blocks and corresponding button holes, the joint strength between the seat and the chair legs can be further enhanced by the complementary fixing achieved by the joint action between the tenons and mortise holes.