The invention relates to a conveniently assembled illuminating lamp. The conveniently assembled illuminating lamp comprises a lamp shell, wherein fixed seats are fixedly mounted on the inner walls oftwo sides of the lamp shell; a lampshade is arranged at the bottom of the lamp shell; a first groove is formed in the bottom of each fixed seat; a positioning groove is formed in the inner wall in oneside of the first groove; a connecting rod is fixedly mounted on the top of the lampshade, and the connecting rod is movably mounted in the corresponding first groove; a positioning pin is fixedly mounted on one side of the connecting rod, and the positioning pin is adaptive to the corresponding positioning groove; and a slot is formed in the top of the positioning pin. By matching a push rod, abayonet lock, a spring, the slots, the positioning pins and the positioning grooves, the push rod is moved to drive the bayonet lock to move, and the bayonet lock compresses the spring, so that the bayonet lock is separated from the slot and is stored in a second groove, and therefore, a purpose of removing fixation of the positioning pin is achieved. The lampshade is moved in the horizontal direction, so that the positioning pins are separated from the positioning grooves. Then the lampshade is moved downward, so that the lampshade is detached, and therefore, the lamp shell is mounted conveniently.