In order to obtain the long-acting FSH preparation, the single strand long-acting analogous gene FSHb-CTP-a was successfully constructed by the C-terminal peptide(CTP) of carboxyl-terminal region of human chorionic gonadotropin with the goat FSHα-subunit and b-subunit genes, then it was inserted into pPIC9K vector.The recombinant plasmid pPIC9K FSHb-CTP-a was transformed into Pichia pastoris GS115 by electroporation. The multi-copy inserts His+Mut+ were gained by the screening of pheno-type and hyper-resistance to G418.After methanol induction, the supernatant was analysised by SDS-Polyacrylamide Gen Electro-phoresis and Western blot. The results show that the transformants of FSHb-CTP-a could express the objective protein successfully and the molecular weight is about 29 kD. The concentration of supernatant was detected by Radio-immunoassay and the average expression of multi-inserts is 91.849 mIU/mL and the low-inserts is 37.419 mIU/mL. The expression of multi-inserts is higher than the low-inserts significantly. This research lay the foundation for studying the structure of FSH and the production of long-acting FSH preparation.