A stepwise combined sockets for Christmas lights includes a pair of first and second sockets stepwise combined together with the first socket higher the second socket, a vertical space form between the pair of socket slightly extended into second socket, a first inlaid groove in an inner periphery of the second socket and pair of second inlaid groove respectively formed in an inner periphery of the sockets opposite to the vertical space for engaging a pair of single contact plates from a first and a second electric wires, a bent common contact plate striding over the two socket having an upper vertical portion disposed into the first socket a transverse portion stopping on the bottom of the vertical space and a lower vertical portion engaged within the first inlaid groove in the second socket, a wrapper ring wrapped the upper rim of the first socket having a downward projection from a side thereof blocking the vertical space, the projection having a lower end stopped against the transverse portion of the common contact plate and a third inlaid groove in an inner side to engaged with the upper vertical portion of the common contact plate, and a pair of lamps respectively inserted into the upper rim of the socket each including a base, a bulb on the base and pair of lead-in wires attached to the outer lateral sides of the base respectively engaged with the common contact plate and the single contact plates.