Abstract: In order to exploit and conserve the genic resources in soybean, it is necessary to analyse the genetic structure of soybean population. The modified procedures detecting the allozymes of Sp 1 (coding β-amylases) and Ti (coding soybean trypsin inhibitors) are summarized as follows: After proteins of soybean seed were separated by using 7% polyacrylamide slab gel electrophoresis (Davis system), gel was soaked in starch solution for half an hour. After that, gel was washed by distilled water twice. Finally, gel was stained by using I2-KI solution (in 0.05N HCl) for 2–3 h. The blank bands in blue back-ground are β-amylases. The products of Sp1a and Sp 1b located at Rf=0.38–0.40 and Rf=0A4–0.47 respectively. The dark blue bands are proteins. The altozymes of Ti can be identified by co-electrophoresis with standard soybean trypsin inhibitors.