A Blumlein microstrip photoconductor switch (P.S.)of high-efficiency isdescribed for the first time in this paper. The output characteristics of the P.S.circuit andthe working properties of the P.S. driven by various laser powers are discussed in theory. Theorical analysis shows that the P.S. has 100% voltage transmission efficiency. Voltagetransmission efficiency of 93% has been obtained in experiment that in agreement with theresult of theory.