This paper describes the method of a phase-alternating composite π pulse sequences, in which the subroutines are programed instead of the previously reported “IMSL” library DUNSJ to solve the non-linear least square problems, being used to minimize the pulse angles with respect to resonance off-set. The main program and subroutines were carried out on a personal computer. It is found that the results from the new program were in agreement with that reported in the reference being obtained from IBM/3600 computer and the present method is more effeciant than other existing pulse sequences.