Abstract: In the disclosure, a power rail expansion joint without expansion gap is provided, which comprises two power rail sections, a limiting guide block, a sliding contact plate and an electric conductor. The two power rail sections cooperate with the limiting guide block, with a sliding clearance therebetween. At least one sliding contact plate is mounted on the limiting guide block or base bodies of the power rail sections, and has a contact surface of the sliding contact plate arranged in a same working surface with outer contact surfaces of the power rail sections. The sliding contact plate is configured to partially or completely cover an expansion separation between the two power rail sections. The sliding contact plate comprises at least one edge which is in an angle of less than 90° with respect to an expansion or contraction direction of the power rail sections.