diff --git a/pyblock3/block2/io.py b/pyblock3/block2/io.py
index ba0bb19..29081a1 100644
--- a/pyblock3/block2/io.py
+++ b/pyblock3/block2/io.py
@@ -162,6 +162,7 @@ def to_block2(mps, center=None, basis=None, tag='KET', save_dir=None):
                 p.n_states[ix] = v
             p.sort_states()
         minfo.tag = tag
+        minfo.bond_dim = minfo.get_max_bond_dimension()
         minfo.save_mutable()
         minfo.save_data("%s/%s-mps_info.bin" % (save_dir, tag))
         tensors = [None] * len(mps)