Abstract: In order to indicate the influences of cassava leaf photosynthetic rate on roots yield in the present study, the proteomic methods was used to analyze the differences of photosynthetic capacity in both cassava genotypes ZM-Seaside (high yield) and mosaic-leaf mutation (low yield) to reveal the different reason of their root yield and provide theoretical basis for the selection of high yield cassava varieties. The leaf net photosynthetic rate (Pn), stomatal conductance (Cs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were measured using a portable analyzer LI-6400. Western blot was used to analysis of protein expression level. Leaf global proteins were extracted by phenol extraction, and then were separated using two-dimensional electrophoresis. Delta 2D software was used to determine the differentially expressed proteins. The differentially expressed proteins were identified using MALDI-TOF-MS in combination with the KEGG database to classify proteins according to their functions. The results showed leaf Pn in ZM-Seaside was significantly increased more than that of mosaic-leaf mutation, while Cs, Ci and Tr in both genotypes were no significant differences. Western blot revealed that the expression levels of Rubisco, OEC and PRXQ, related with photosynthetic pathway, in ZM-Seaside was significantly higher than that of mosaic-leaf mutation. 20 different protein spots were detected in the leaves of ZM-Seaside compared with mosaic-leaf mutation, of which 15 were up-regulated, 5 was down-regulated. Sixteen protein spots were successfully identified, in which they involved in photosynthesis (3), carbohydrate and energy metabolism (4), chaperones (2), structure (2), defense (1), detoxifying and antioxidant (2), and unknown functions (2). Ribulose-5-phosphate-3-epimerase and chloroplast latex aldolase-like protein were theorized as key proteins through the network of differential protein-protein interaction. The root yield of cassava ZM-Seaside was improved probably based on their up-regulation in leaves.