The influence of La and Nd complexes with citric acid on the cellulase activity for the different cellulose was studied. The La and Nd complexes with citric acid were synthesized by the deposition method. The content of the La and Nd in the complexes was analyzed by the method of EDTA titration.The complexes were coordinated with the carboxyl of citric acid. The activity of the cellulase, which is the quantity(μg) of gained dextrose from the enough cellulose per mg cellulase per minute, was determined with the DNS method. The results reveal that the La and Nd complexes with citric acid respectively could stimulate the cellulase activity and maximize the activity at 1.0×10 -8 g·L -1 or 1.0×10 -9 g·L -1, which is the concentration of La 3+ or Nd 3+, for the different cellulose, such as filter paper, CM-Cellulose Na and Cellobiose. The influence of Nd complex on the cellulase activity is stronger than that of La complex. The influence of La and Nd complexes with citric acid on the cellulase activity for the different cellulose was studied. The La and Nd complexes with citric acid were synthesized by the deposition method. The content of the La and Nd in the complexes was analyzed by the method of EDTA titration.The complexes were coordinated with the carboxyl of citric acid. The activity of the cellulase, which is the quantity (μg) of gained dextrose from the enough cellulose per mg cellulase per minute, was determined with the DNS method. The results reveal that the La and Nd complexes with citric acid respectively could stimulate the cellulase activity and maximize the activity at 1.0 × 10 -8 g · L -1 or 1.0 × 10 -9 g · L -1, which is the concentration of La 3+ or Nd 3+, for the different cellulose, such as filter paper, CM-Cellulose Na and Cellobiose. The influence of Nd complex on the cellulase activity is stronger than that of La complex.