diff --git a/deepmd/utils/argcheck.py b/deepmd/utils/argcheck.py
index 5748ad9bf7..680d7a9007 100644
--- a/deepmd/utils/argcheck.py
+++ b/deepmd/utils/argcheck.py
@@ -1287,7 +1287,8 @@ def training_data_args():  # ! added by Ziyao: new specification style for data
 - int: all {link_sys} use the same batch size.\n\n\
 - string "auto": automatically determines the batch size so that the batch_size times the number of atoms in the system is no less than 32.\n\n\
 - string "auto:N": automatically determines the batch size so that the batch_size times the number of atoms in the system is no less than N.\n\n\
-- string "mixed:N": the batch data will be sampled from all systems and merged into a mixed system with the batch size N. Only support the se_atten descriptor.'
+- string "mixed:N": the batch data will be sampled from all systems and merged into a mixed system with the batch size N. Only support the se_atten descriptor.\n\n\
+If MPI is used, the value should be considered as the batch size per task.'
     doc_auto_prob_style = 'Determine the probability of systems automatically. The method is assigned by this key and can be\n\n\
 - "prob_uniform"  : the probability all the systems are equal, namely 1.0/self.get_nsystems()\n\n\
 - "prob_sys_size" : the probability of a system is proportional to the number of batches in the system\n\n\