The coupling efficiency of the pump coupler determines the pump light injection capacity of a laser system. We have designed a pump coupler in a series connection, of which two or more pump couplers are spliced together through signal fibers to form a new pump coupler with high coupling efficiency and high output power. In the experiment, 3×1 end-pumping couplers and (2+1)×1 side-pumping couplers were made respectively and the two couplers were spliced to form a series connection. Six LDs with output power of about 200 W respectively were spliced with the six pumping arms of the new pump coupler. A total output power of this series connection pump coupler was about 1160 W, corresponding to a coupling efficiency as high as 98%. The loss of signal light was less than 0.4%.