Abstract: Using convinientable photosynthetic analyzer to study changes of photosynthetic rate (Pn)of different genotype malting barley,analysis the effect for yield.The results showed that: LAI of tow-rowed malting barley M-22、KH LEDI、Pasadena、Z014J081J、MERIT、Z090M066M were all high, LAI of American genetype Z014J081J was maximum, it’s value was 2.69; There was a positive correlation between LAI and yield of different genotype malting barley,From flag leaf stage to later filling stage, the correlation between LAI and yield was very significant; Relational analysis shows, There was a positive correlation between photosynthetic rate (Pn)and yield of different genotype malting barley. The correlation between Pn and yield was very significant at booting,heading to flowering and later filling stage, the correlation index was 0.5024,0.5359,0.6758.