Our previous synthesis of the sex pheromone of pink bollworm hag been improved in the following way(Reaotion scheme in the Chinese Teat),namely: (1)8 was prepared from lithium salt of 10 with m,-butylbmmide in liquid ammonia; (2) 4 was prepared from 8 by LiA1H₄ reduction; (3) 1:1 mixture of 8 and 4 was used in the preparation of 1:1 Z and E mizture of 5,the mistnre was subjected to the reaction sequence: 5→7→11→1+2; (4) multipositional isomerisation of 8 with sodium 3-aminopropylamide gave 9.A 1:1 mixture of 1 and 2 was prepared from the ethylene oxide and acetylene through eight steps in an overall yield of 37.The directly synthesized 1:1 mixture of 1 and 2 is a very good attractant to the malo pink bollworm moth in the field teat.