An efficient and simple method for purification of human thymic peptides (HTP) by preparative electrofocusing in immobil pH gradients is recommended. The fresh human fetus tissues were collected and treated in steps by heat denatu-ration, acetone precipitation and ultrafiltration. The ultrafiltrate (mHTP) was separated by preparative electrofocusing in immobil pH gradients. Four peptides, HTPα,β,β2 and γ1 in mg level were successfully purified from one gel plate with dimensions 110 ×240× 2mm. The isoelectrie points of these purified peptides are 4.6, 5.3. 5.8 and 7.6, and the molecular weights estimated by SDS-PAGE are 4,800, 6,700, 7,200-7,300 and 12,000-13,000 dalton respectively. The four purified HTPs were shown to maintain high activities in both E-rosette assay and TdT activity test.