By using the hydroxyethyl crosslinked chitosan beads as the support, a novel immunoadsorbent was prepared by conjugating DNA onto the beads via the CNBr activation. The influence of conditions on the immobilization capacity of DNA was studied in detail. The adsorption experiments were performed by adding the immunoadsorbents to the SLE serum. The results showed that this type of immunoadsorbent could cut down the anti-DNA antibody levels by 65.33% at most in serum. Because the chitosan has good blood compatibility, this type of immunoadsorbent is hopeful for the treatment of SLE by hemoperfusion in the future.