Abstract:The purpose of this study was to examine the superoxide dismutase (SOD) zymogram patterns, their frequency and geographical distribution of wild (Glycine soja) and cultivated soybean (G. max) in China. Seeds of 226 wild soybean germplasms and 104 cultivated soybean cultivars (land races) were collected from all provinces and autonomous regions in China except Taiwan, Xinjiang and Qinghai provinces About 50 embryos per wild soybean germplasm and I0 embryos per cultivated soybean cultivars were used for test. Vertical polyacrylamide gel electrophoresis and a stainning system modified after Luo (1984)were used. The Japanese GS- 930 Scanner was used in gel-plate scanning. In program scanning the maximum and minimum absorption wavelength were 700 and 550 nm respectively. The results showed that: 1. Six zymogram patterns were found in soybean (Fig. 1, 2). Wild soybean displayed five patterns (Ⅰ, Ⅱ, Ⅳ Ⅴ, Ⅵ), while the cultivated soybean displayed only two patterns (Ⅱ, Ⅲ). 2. Fourty six percent of wild germplasms gave an 7-band zymogram (Table Ⅰ) (pattern Ⅰ), fourty nine percent had a 6th and 7th band with faster mobility (pattern Ⅱ), about two percent produced a 6-band zymogram which lacked the SODc4 band (pattern Ⅳ), about two percent had a 5-band pattern which lacked the SODc,c4 bands (pattern Ⅴ), and only one germptasm displayed a 5-band zymogram which lacked SODb2b3 bands (pattern Ⅵ). 3. More than ninty eight percent of cultivated cultivars belonged to pattern Ⅱ, only about two percent belonged to pattern Ⅲ. 4. The geographical distribution of frequency of pattern Ⅱ between wild and cultivated soybean was most close in 36–51º N area. The difference of zymograms between G. soja and G. max, and the problems of the origional area and evolution of soybean were discussed.