  The directed and elliptic flow in collisions of $^{112}Sn$ + $^{112}Sn$ at
energies from 35 to 90 MeV/nucleon were studied in an isospin-dependent quantum
molecule dynamics model (IQMD). With increasing incident energy, the directed
flow rises from the negative flow to the positive flow. Its magnitude depends
on the nuclear equation of state (EOS). However, the elliptic flow shows
decrease with increasing incident energy and its magnitude is not very sensible
to EOS. Systematic studies of the impact parameter dependence and cluster mass
dependence were also performed. The study of directed flow at intermediate
energies thus provides a means to extract the information on the nuclear
equation of state.
