Partition-and-Shift codes have been paid much attention in the area of error correction in telecommunication system,because of its ideal girth and min-distance property.An Improved algorithm for constructing PS-LDPC codes is presented to improve constructing efficiency,by employing a precise criterion for choosing the shift parameters in shift matrix and a perspicuous and reasonable method to search for closed paths simply.Finally,the improved PS-LDPC codes are simulated over AWGN channel and a better BER performance is obtained.