Abstract：Effect of cholesteryl grafted sodium alginate derivative (CSAD) on wettability and deposition capacity of lambda-cyhalothrin in water emulsion on the banana leaf surface was investigated in terms of dynamic and static surface tension, contact angle, retention and pesticide adsorption capacity by the inverse emulsion method, which was adopted to prepare the lambda-cyhalothrin in water emulsion by alkyl indican (APG) as the emulsifie. The results showed that both the CSAD+APG system and the APG system stable water emulsion had a similar critical micelle concentration(i.e., 0.1 g/L of CAPG). In addition, for the two systems as the CAPG was equal to 0.1 g/L, the maximum retention capacity on leaves was 0.0104 and 0.00778 g/cm2, the adhesion tension was 24.32 and 16.14 mN/m and the adhesion work was 55.23 and 46.47 mN/m, respectively. Furthermore, the CSAD+APG system showed a much higher pesticide adsorption capacity on leaves that was 524 μg/L, while the corresponding value of the APG system was only 412 μg/L. In general, the addition of the amphiphilic CSAD could effectively enhance the retention and adsorption capacity of water emulsion on banana leaves due to the formation of CSAD-APG complexes adsorbed at the solid-liquid interface.