The complex oftecbium with L-aspartic acid was separated in solid form. The complex structure was studied by the elementary-analysis, thermal analysis and infra-red absorption spectroscopy methods. Solid complex substance contains the component Tb(HAsp)3.3H2O. Biological activity of the complex was indicated. At the concentration of from 30 ppm to 240 ppm, the complex has influence on the inhibit sprout and peanut development, inhibits are increased according to the concentration. The complex has inhibiting capacity which seems to be better than that of central ion but to be worse than that of ligand.