An increasing number of small biosamples (e.g. proteins and enzymes) need micropreparation in lab. However, neither large-scale free-flow electrophoresis (LS-FFE) nor chip FFE (C-FFE) could fit the growing demands. Herein, a simple quasi-chip FFE (QC-FFE) was constructed. In contrast to C-FFE, the features of QC-FFE are as follows: (i) its separation chamber is reassemblable and rewashable avoiding discard of C-FFE due to blockage of solute precipitation in chamber; (ii) its chamber size is 45 mm x 30mm x (80500)mu m (108654 mu L volume) having function of micropreparation; (iii) there are up to 16 outlets in QC-FFE bestowing fine fraction for micropurification. The QC-FFE was used for the micropurification of model enzyme of self-digestible trypsin in crude pancreatin. Under the given conditions, the purification factor of enzyme was 11.7, the specific activity reached 6236 U/mg, the run time for 19 mu L sample purification was 45 s and the throughput of trypsin was 3.34 mg/h, and the yield of pure trypsin was 55.2%. All of the results show the feasibility of enzyme micropreparation via QC-FFE. The developed device and procedure have potential use to other micropurification of protein or peptide sample.